What can Obama do about Russia’s invasion of Crimea?

Tom Cohen and Dana Davidsen, CNN
Updated 7:41 AM EST, Tue March 4, 2014
Ukrainian tanks are transported from their base in Perevalne, Crimea, on Wednesday, March 26. After Russian troops seized most of Ukraine's bases in Crimea, interim Ukrainian President Oleksandr Turchynov ordered the withdrawal of armed forces from the peninsula, citing Russian threats to the lives of military staff and their families.
Crisis in Ukraine —
Ukrainian tanks are transported from their base in Perevalne, Crimea, on Wednesday, March 26. After Russian troops seized most of Ukraine's bases in Crimea, interim Ukrainian President Oleksandr Turchynov ordered the withdrawal of armed forces from the peninsula, citing Russian threats to the lives of military staff and their families.
Pavel Golovkin/aP
Ukrainian marines wave as they leave a base in Feodosia, Crimea, on Tuesday, March 25.
Crisis in Ukraine —
Ukrainian marines wave as they leave a base in Feodosia, Crimea, on Tuesday, March 25.
Valeriy Kulyk/AP
Russian sailors stand on the deck of the corvette ship Suzdalets in the bay of Sevastopol, Crimea, on March 25.
Crisis in Ukraine —
Russian sailors stand on the deck of the corvette ship Suzdalets in the bay of Sevastopol, Crimea, on March 25.
VIKTOR DRACHEV/AFP/Getty Images
Pro-Russian militia members remove a local resident as Russian troops assault the Belbek air base, outside Sevastopol, on Saturday, March 22. Following its annexation of Crimea, Russian forces have consolidated their control of the region.
Crisis in Ukraine —
Pro-Russian militia members remove a local resident as Russian troops assault the Belbek air base, outside Sevastopol, on Saturday, March 22. Following its annexation of Crimea, Russian forces have consolidated their control of the region.
Ivan Sekretarev/AP
Soldiers in unmarked uniforms sit atop an armored personnel carrier at the gate of the Belbek air base on March 22.
Crisis in Ukraine —
Soldiers in unmarked uniforms sit atop an armored personnel carrier at the gate of the Belbek air base on March 22.
Ivan Sekretarev/AP
A Russian sailor holds the Russian Navy's St. Andrew's flag while standing on the bow of the surrendered Ukrainian submarine Zaporozhye on March 22 in Sevastopol.
Crisis in Ukraine —
A Russian sailor holds the Russian Navy's St. Andrew's flag while standing on the bow of the surrendered Ukrainian submarine Zaporozhye on March 22 in Sevastopol.
SERGEI ILNITSKY/EPA /LANDOV
Russian President Vladimir Putin signs the final decree completing the annexation of Crimea on Friday, March 21, as Upper House Speaker Valentina Matviyenko, left, and State Duma Speaker Sergei Naryshkin watch.
Crisis in Ukraine —
Russian President Vladimir Putin signs the final decree completing the annexation of Crimea on Friday, March 21, as Upper House Speaker Valentina Matviyenko, left, and State Duma Speaker Sergei Naryshkin watch.
Sasha Mordovets/Getty Images
A Ukrainian serviceman leaves a Ukrainian military unit that Russian soldiers took control of in Perevalne on March 21.
Crisis in Ukraine —
A Ukrainian serviceman leaves a Ukrainian military unit that Russian soldiers took control of in Perevalne on March 21.
YURI KOCHETKOV/EPA/LANDOV
Ukrainian border guards run during training at a military camp in Alekseyevka, Ukraine, on March 21.
Crisis in Ukraine —
Ukrainian border guards run during training at a military camp in Alekseyevka, Ukraine, on March 21.
Sergei Grits/AP
Russian soldiers patrol the area surrounding a Ukrainian military unit in Perevalne on Thursday, March 20.
Crisis in Ukraine —
Russian soldiers patrol the area surrounding a Ukrainian military unit in Perevalne on Thursday, March 20.
FILIPPO MONTEFORTE/AFP/Getty Images
Pro-Russian protesters remove the gate to the Ukrainian navy headquarters as Russian troops stand guard in Sevastopol on Wednesday, March 19.
Crisis in Ukraine —
Pro-Russian protesters remove the gate to the Ukrainian navy headquarters as Russian troops stand guard in Sevastopol on Wednesday, March 19.
Vasiliy BATANOV/AFP/Getty Images
Pro-Russian forces walk inside the Ukrainian navy headquarters in Sevastopol on March 19.
Crisis in Ukraine —
Pro-Russian forces walk inside the Ukrainian navy headquarters in Sevastopol on March 19.
Andrew Lubimov/AP
A member of pro-Russian forces takes down a Ukrainian flag at the Ukrainian navy headquarters in Sevastopol on March 19.
Crisis in Ukraine —
A member of pro-Russian forces takes down a Ukrainian flag at the Ukrainian navy headquarters in Sevastopol on March 19.
Andrew Lubimov/AP
Alexander Vitko, chief of the Russian Black Sea Fleet, leaves the Ukrainian navy headquarters in Sevastopol after pro-Russian forces took it over on March 19.
Crisis in Ukraine —
Alexander Vitko, chief of the Russian Black Sea Fleet, leaves the Ukrainian navy headquarters in Sevastopol after pro-Russian forces took it over on March 19.
Andrew Lubimov/AP
A Russian flag waves as workers install a new sign on a parliament building in Simferopol, Crimea's capital, on March 19.
Crisis in Ukraine —
A Russian flag waves as workers install a new sign on a parliament building in Simferopol, Crimea's capital, on March 19.
Vadim Ghidra/AP
Russian military personnel surround a Ukrainian military base in Perevalne on March 19.
Crisis in Ukraine —
Russian military personnel surround a Ukrainian military base in Perevalne on March 19.
Dan Kitwood/Getty Images
Nameplates on the front of the Crimean parliament building get removed Tuesday, March 18, in Simferopol.
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Nameplates on the front of the Crimean parliament building get removed Tuesday, March 18, in Simferopol.
Bulent Doruk/Anadolu Agency/Getty Images
From left, Crimean Prime Minister Sergey Aksyonov; Vladimir Konstantinov, speaker of the Crimean parliament; Russian President Vladimir Putin; and Alexei Chaly, the new de facto mayor of Sevastopol, join hands in Moscow on March 18 after signing a treaty to make Crimea part of Russia.
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From left, Crimean Prime Minister Sergey Aksyonov; Vladimir Konstantinov, speaker of the Crimean parliament; Russian President Vladimir Putin; and Alexei Chaly, the new de facto mayor of Sevastopol, join hands in Moscow on March 18 after signing a treaty to make Crimea part of Russia.
YEKATERINA SHTUKINA/AFP/Getty Images
Demonstrators hold a Crimean flag at Lenin Square in Simferopol on March 18.
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Demonstrators hold a Crimean flag at Lenin Square in Simferopol on March 18.
FILIPPO MONTEFORTE/AFP/Getty Images
Ukrainian soldiers stand guard at a checkpoint near Strilkove, Ukraine, close to Crimea on Monday, March 17.
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Ukrainian soldiers stand guard at a checkpoint near Strilkove, Ukraine, close to Crimea on Monday, March 17.
IVAN BOBERSKYY/EPA/LANDOV
Former boxer and Ukrainian politician Vitali Klitschko addresses reporters in Kiev, Ukraine, on March 17.
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Former boxer and Ukrainian politician Vitali Klitschko addresses reporters in Kiev, Ukraine, on March 17.
Artyom Geodakyan/ITAR-TASS/Landov
Ukrainian troops stand guard in front of the Ukrainian Parliament building in Kiev on March 17.
Crisis in Ukraine —
Ukrainian troops stand guard in front of the Ukrainian Parliament building in Kiev on March 17.
SERGEI SUPINSKY/AFP/Getty Images
A Ukrainian man applies for the National Guard at a mobile recruitment center in Kiev on March 17.
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A Ukrainian man applies for the National Guard at a mobile recruitment center in Kiev on March 17.
ROBERT GHEMENT/EPA/LANDOV
Civilians walk past riot police in Simferopol on March 17.
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Civilians walk past riot police in Simferopol on March 17.
Dan Kitwood/Getty Images
A Ukrainian soldier stands on top of an armored vehicle at a military camp near the village of Michurino, Ukraine, on March 17.
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A Ukrainian soldier stands on top of an armored vehicle at a military camp near the village of Michurino, Ukraine, on March 17.
Sergei Grits/AP
Policemen stand guard outside the regional state administration building in Donetsk, Ukraine, during a rally by pro-Russia activists March 17.
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Policemen stand guard outside the regional state administration building in Donetsk, Ukraine, during a rally by pro-Russia activists March 17.
KHUDOTEPLY/AFP/Getty Images
Armed soldiers stand guard outside a Ukrainian military base in Perevalne on March 17.
Crisis in Ukraine —
Armed soldiers stand guard outside a Ukrainian military base in Perevalne on March 17.
Spencer Platt/Getty Images
A man holds a Crimean flag as he stands in front of the Crimean parliament building in Simferopol on March 17.
Crisis in Ukraine —
A man holds a Crimean flag as he stands in front of the Crimean parliament building in Simferopol on March 17.
DIMITAR DILKOFF/AFP/Getty Images
Crimeans holding Russian flags celebrate in front of the parliament building in Simferopol on Sunday, March 16.
Crisis in Ukraine —
Crimeans holding Russian flags celebrate in front of the parliament building in Simferopol on Sunday, March 16.
XINHUA /LANDOV
A Ukrainian police officer tries to shield himself from a road block thrown by pro-Russia supporters in Kharkiv, Ukraine, on March 16.
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A Ukrainian police officer tries to shield himself from a road block thrown by pro-Russia supporters in Kharkiv, Ukraine, on March 16.
Sergei Chuzavkov/AP
Pro-Russia demonstrators storm the prosecutor general's office during a rally in Donetsk on March 16.
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Pro-Russia demonstrators storm the prosecutor general's office during a rally in Donetsk on March 16.
Andrey Basevich/AP
A child casts her mother's ballot March 16 while holding a Russian flag at a polling station in Simferopol.
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A child casts her mother's ballot March 16 while holding a Russian flag at a polling station in Simferopol.
VIKTOR DRACHEV/AFP/Getty Images
A pro-Russian soldier, with the Russian flag behind him, mans a machine gun outside an Ukrainian military base in Perevalne on Saturday, March 15.
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A pro-Russian soldier, with the Russian flag behind him, mans a machine gun outside an Ukrainian military base in Perevalne on Saturday, March 15.
Vadim Ghirda/AP
A pro-Russian soldier guards the perimeter outside an Ukrainian military base in Perevalne on March 15.
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A pro-Russian soldier guards the perimeter outside an Ukrainian military base in Perevalne on March 15.
Vadim Ghirda/AP
Russian flags wave in front of a monument dedicated to Soviet Union founder Vladimir Lenin during a pro-Russia rally in Simferopol's Lenin Square on March 15.
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Russian flags wave in front of a monument dedicated to Soviet Union founder Vladimir Lenin during a pro-Russia rally in Simferopol's Lenin Square on March 15.
Dan Kitwood/Getty Images
Evgenyi Batyukhov cries March 14 at the site where pro-Russian and pro-Ukrainian activists clashed the night before in Donetsk, Ukraine.
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Evgenyi Batyukhov cries March 14 at the site where pro-Russian and pro-Ukrainian activists clashed the night before in Donetsk, Ukraine.
Sergei Grits/AP
A line of policemen stand in front of a bus of pro-Ukrainian activists as pro-Russian supporters confront them during a rally in Donetsk on Thursday, March 13.
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A line of policemen stand in front of a bus of pro-Ukrainian activists as pro-Russian supporters confront them during a rally in Donetsk on Thursday, March 13.
Alexander KHUDOTEPLY/AFP/Getty Images
Pro-Russian supporters clash with pro-Ukrainian activists in Donetsk on March 13.
Crisis in Ukraine —
Pro-Russian supporters clash with pro-Ukrainian activists in Donetsk on March 13.
Alexander KHUDOTEPLY/AFP/Getty Images
Recent Academy Award winner Jared Leto walks through Independence Square in Kiev on March 13. During his Oscars acceptance speech in early March, the actor spoke to protesters in Ukraine and Venezuela saying, "We're thinking of you tonight."
Crisis in Ukraine —
Recent Academy Award winner Jared Leto walks through Independence Square in Kiev on March 13. During his Oscars acceptance speech in early March, the actor spoke to protesters in Ukraine and Venezuela saying, "We're thinking of you tonight."
Sergey Starostenko/Kommersant Photo via Getty Images
A member of a pro-Russian self-defense unit checks a polling station near Simferopol on March 13.
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A member of a pro-Russian self-defense unit checks a polling station near Simferopol on March 13.
Manu Brabo/AP
A Ukrainian soldier looks out of the window of a regional military building with a poster reading "Ukraine's armed forces wait for you!" in Donetsk on March 13.
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A Ukrainian soldier looks out of the window of a regional military building with a poster reading "Ukraine's armed forces wait for you!" in Donetsk on March 13.
Sergei Grits/AP
An armed Cossack stands guard at a checkpoint on the road from Simferopol to Sevastopol on March 13.
Crisis in Ukraine —
An armed Cossack stands guard at a checkpoint on the road from Simferopol to Sevastopol on March 13.
FILIPPO MONTEFORTE/AFP/Getty Images
A pro-Russian soldier speaks to a truck driver outside the Ukrainian infantry base in Perevalne on Wednesday, March 12.
Crisis in Ukraine —
A pro-Russian soldier speaks to a truck driver outside the Ukrainian infantry base in Perevalne on Wednesday, March 12.
Vadim Ghirda/AP
Cossacks stand guard at Crimea's regional parliament building in Simferopol on March 12.
Crisis in Ukraine —
Cossacks stand guard at Crimea's regional parliament building in Simferopol on March 12.
FILIPPO MONTEFORTE/AFP/Getty Images
Soldiers are seen aboard the Ukrainian ship Slavutych in the harbor of Sevastopol on Tuesday, March 11.
Crisis in Ukraine —
Soldiers are seen aboard the Ukrainian ship Slavutych in the harbor of Sevastopol on Tuesday, March 11.
FILIPPO MONTEFORTE/AFP/Getty Images
Ukrainian naval officers board a boat in front of the Russian minesweeper Turbinist in Sevastopol's harbor on March 11.
Crisis in Ukraine —
Ukrainian naval officers board a boat in front of the Russian minesweeper Turbinist in Sevastopol's harbor on March 11.
FILIPPO MONTEFORTE/AFP/Getty Images
People shout slogans during a pro-Russia rally in Donetsk on Sunday, March 9.
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People shout slogans during a pro-Russia rally in Donetsk on Sunday, March 9.
Sergei Grits/AP
Ukrainian police detain a demonstrator during a pro-Russian rally in Donetsk on March 9.
Crisis in Ukraine —
Ukrainian police detain a demonstrator during a pro-Russian rally in Donetsk on March 9.
Sergei Grits/AP
Pro-Russia protesters remove a Ukrainian flag from a flagpole taken from a government building in Donetsk on March 9.
Crisis in Ukraine —
Pro-Russia protesters remove a Ukrainian flag from a flagpole taken from a government building in Donetsk on March 9.
Sergei Grits/AP
Cossacks and other pro-Russian forces stand guard outside a government building in Simferopol on Saturday, March 8.
Crisis in Ukraine —
Cossacks and other pro-Russian forces stand guard outside a government building in Simferopol on Saturday, March 8.
Manu Brabo/AP
Ukrainian soldiers load armored personnel carriers into boxcars in the western Ukrainian city of Lviv on March 8.
Crisis in Ukraine —
Ukrainian soldiers load armored personnel carriers into boxcars in the western Ukrainian city of Lviv on March 8.
YURIY DYACHYSHYN/AFP/Getty Images
Armed men believed to be Russian military march in a village outside Simferopol on Friday, March 7.
Crisis in Ukraine —
Armed men believed to be Russian military march in a village outside Simferopol on Friday, March 7.
MAXIM SHIPENKOV/EPA/LANDOV
Pro-Russia protesters demonstrate outside the Belbek air base, near Sevastopol, on Thursday, March 6.
Crisis in Ukraine —
Pro-Russia protesters demonstrate outside the Belbek air base, near Sevastopol, on Thursday, March 6.
FILIPPO MONTEFORTE/AFP/Getty Images
A Ukrainian navy officer looks at the scuttled, decommissioned Russian vessel Ochakov from the Black Sea shore outside the town of Myrnyi, Ukraine, on March 6. Russian naval personnel scuttled the ship, blockading access for five Ukrainian naval vessels.
Crisis in Ukraine —
A Ukrainian navy officer looks at the scuttled, decommissioned Russian vessel Ochakov from the Black Sea shore outside the town of Myrnyi, Ukraine, on March 6. Russian naval personnel scuttled the ship, blockading access for five Ukrainian naval vessels.
Darko Vojinovic/AP
A member of the Russian military patrols around Perevalne on March 6.
Crisis in Ukraine —
A member of the Russian military patrols around Perevalne on March 6.
Maxppp/Landov
Servicemen guard a checkpoint at a Ukrainian navy base in Perevalne on March 6.
Crisis in Ukraine —
Servicemen guard a checkpoint at a Ukrainian navy base in Perevalne on March 6.
Stanislav Krasilnikov/ITAR-TASS/Landov
Ukrainian troops guard the Belbek air base on March 6.
Crisis in Ukraine —
Ukrainian troops guard the Belbek air base on March 6.
ZURAB KURTSIKIDZE/EPA/LANDOV
A woman walks past barricades March 6 that were set up by anti-government protesters in Kiev's Independence Square.
Crisis in Ukraine —
A woman walks past barricades March 6 that were set up by anti-government protesters in Kiev's Independence Square.
Emilio Morenatti/AP
A sailor guards the Ukrainian Navy ship Slavutych in the Bay of Sevastopol on Wednesday, March 5.
Crisis in Ukraine —
A sailor guards the Ukrainian Navy ship Slavutych in the Bay of Sevastopol on Wednesday, March 5.
VIKTOR DRACHEV/AFP/Getty Images
People wait in line for food distribution in Independence Square on March 5.
Crisis in Ukraine —
People wait in line for food distribution in Independence Square on March 5.
DIMITAR DILKOFF/AFP/Getty Images
Ukrainian sailors carry meat to their vessel in the Sevastopol harbor on March 5.
Crisis in Ukraine —
Ukrainian sailors carry meat to their vessel in the Sevastopol harbor on March 5.
courtesy Denis Sinyakov
Riot police stand at the entrance of a regional administrative building during a rally in Donetsk on March 5.
Crisis in Ukraine —
Riot police stand at the entrance of a regional administrative building during a rally in Donetsk on March 5.
Sergei Chuzavkov/AP
A Ukrainian police officer gives instructions to members of the media in front of the business class lounge of the Simferopol airport on March 5.
Crisis in Ukraine —
A Ukrainian police officer gives instructions to members of the media in front of the business class lounge of the Simferopol airport on March 5.
Darko Vojinovic/AP
Pro-Russia demonstrators wave a Russian flag after storming a regional administrative building in Donetsk on March 5.
Crisis in Ukraine —
Pro-Russia demonstrators wave a Russian flag after storming a regional administrative building in Donetsk on March 5.
Sergei Chuzavkov/AP
Demonstrators break a police barrier as they storm a regional administrative building in Donetsk on March 5.
Crisis in Ukraine —
Demonstrators break a police barrier as they storm a regional administrative building in Donetsk on March 5.
Sergei Chuzavkov/AP
Ukrainian military recruits line up to receive instructions in Kiev's Independence Square on Tuesday, March 4.
Crisis in Ukraine —
Ukrainian military recruits line up to receive instructions in Kiev's Independence Square on Tuesday, March 4.
Emilio Morenatti/AP
People stand on the Ukrainian Navy ship Slavutych while it's at harbor in Sevastopol on March 4. Mattresses were placed over the side of the ship to hinder any attempted assault.
Crisis in Ukraine —
People stand on the Ukrainian Navy ship Slavutych while it's at harbor in Sevastopol on March 4. Mattresses were placed over the side of the ship to hinder any attempted assault.
Courtesy Andrew Lubimov
Ukrainian troops watch as a Russian navy ship blocks the entrance of the Ukrainian navy base in Sevastopol on March 4.
Crisis in Ukraine —
Ukrainian troops watch as a Russian navy ship blocks the entrance of the Ukrainian navy base in Sevastopol on March 4.
ZURAB KURTSIKIDZE/EPA/LANDOV
A woman photographs pro-Russian soldiers guarding Ukraine's infantry base in Perevalne on March 4.
Crisis in Ukraine —
A woman photographs pro-Russian soldiers guarding Ukraine's infantry base in Perevalne on March 4.
Sergei Grits/AP
U.S. Secretary of State John Kerry, wearing a blue scarf, visits a shrine March 4 for the people who were killed in February during anti-government protests in Kiev.
Crisis in Ukraine —
U.S. Secretary of State John Kerry, wearing a blue scarf, visits a shrine March 4 for the people who were killed in February during anti-government protests in Kiev.
Kevin Lamarque/Pool/AP
Yuli Mamchun, the commander of the Ukrainian military garrison at the Belbek air base near Sevastopol, salutes on March 4.
Crisis in Ukraine —
Yuli Mamchun, the commander of the Ukrainian military garrison at the Belbek air base near Sevastopol, salutes on March 4.
Sean Gallup/Getty Images
Russian soldiers stand guard at the Belbek air base on March 4.
Crisis in Ukraine —
Russian soldiers stand guard at the Belbek air base on March 4.
courtesy Denis Sinyakov
Ukrainian military members march at the Belbek air base on March 4.
Crisis in Ukraine —
Ukrainian military members march at the Belbek air base on March 4.
Ivan Sekretarev/AP
Russian soldiers fire warning shots to keep back Ukrainian military members at the Belbek air base on March 4.
Crisis in Ukraine —
Russian soldiers fire warning shots to keep back Ukrainian military members at the Belbek air base on March 4.
Ivan Sekretarev/AP
A Ukrainian airman puts the Ukrainian national flag over the gate of the Belbek air base as they guard what's left under their control on March 4.
Crisis in Ukraine —
A Ukrainian airman puts the Ukrainian national flag over the gate of the Belbek air base as they guard what's left under their control on March 4.
Ivan Sekretarev/AP
Russian soldiers aim a grenade launcher and machine gun as they guard positions at the Belbek air base on March 4.
Crisis in Ukraine —
Russian soldiers aim a grenade launcher and machine gun as they guard positions at the Belbek air base on March 4.
Ivan Sekretarev/AP
Ukrainian seamen stand guard on the Ukrainian navy ship Slavutych in the Sevastopol harbor on Monday, March 3.
Crisis in Ukraine —
Ukrainian seamen stand guard on the Ukrainian navy ship Slavutych in the Sevastopol harbor on Monday, March 3.
Andrew Lubimov/AP
Oleg, a Ukrainian soldier, kisses his girlfriend, Svetlana, through the gates of the Belbek base entrance on March 3. Tensions are high at the base, where Ukrainian soldiers were standing guard inside the building while alleged Russian gunmen were standing guard outside the gates.
Crisis in Ukraine —
Oleg, a Ukrainian soldier, kisses his girlfriend, Svetlana, through the gates of the Belbek base entrance on March 3. Tensions are high at the base, where Ukrainian soldiers were standing guard inside the building while alleged Russian gunmen were standing guard outside the gates.
Sean Gallup/Getty Images
Wives of Ukrainian soldiers walk past Russian soldiers to visit their husbands guarding a military base in Perevalne on March 3.
Crisis in Ukraine —
Wives of Ukrainian soldiers walk past Russian soldiers to visit their husbands guarding a military base in Perevalne on March 3.
courtesy Denis Sinyakov
A Russian soldier guards an area outside Ukraine's military base in the village of Perevalne on March 3.
Crisis in Ukraine —
A Russian soldier guards an area outside Ukraine's military base in the village of Perevalne on March 3.
courtesy Denis Sinyakov
A sailor looks out a window near the entrance to the Ukrainian navy headquarters in Sevastopol on March 3.
Crisis in Ukraine —
A sailor looks out a window near the entrance to the Ukrainian navy headquarters in Sevastopol on March 3.
Andrew Lubimov/AP
Armed men in military uniform walk outside a Ukrainian military unit near Simferopol on Sunday, March 2. Hundreds of armed men in trucks and armored vehicles surrounded the Ukrainian base Sunday in Crimea, blocking its soldiers from leaving.
Crisis in Ukraine —
Armed men in military uniform walk outside a Ukrainian military unit near Simferopol on Sunday, March 2. Hundreds of armed men in trucks and armored vehicles surrounded the Ukrainian base Sunday in Crimea, blocking its soldiers from leaving.
ALEXEY FURMAN/EPA/LANDOV
Soldiers walk outside a Ukrainian military base in Perevalne as a local resident waves a Russian flag March 2.
Crisis in Ukraine —
Soldiers walk outside a Ukrainian military base in Perevalne as a local resident waves a Russian flag March 2.
Ivan Sekretarev/ap
Demonstrators shout during a rally in Kiev's Independence Square on March 2.
Crisis in Ukraine —
Demonstrators shout during a rally in Kiev's Independence Square on March 2.
Emilio Morenatti/AP
Ukrainian soldiers, left, and unidentified gunmen, right, stand at the gate of an infantry base in Perevalne on March 2.
Crisis in Ukraine —
Ukrainian soldiers, left, and unidentified gunmen, right, stand at the gate of an infantry base in Perevalne on March 2.
Darko Vojinovic/AP
Ukrainian soldiers guard a gate of an infantry base in Perevalne on March 2.
Crisis in Ukraine —
Ukrainian soldiers guard a gate of an infantry base in Perevalne on March 2.
Darko Vojinovic/AP
A woman cries during a rally in Independence Square on March 2.
Crisis in Ukraine —
A woman cries during a rally in Independence Square on March 2.
Sergei Chuzavkov/AP
Protesters hold flags of the United States, Germany and Italy during a rally in Independence Square on March 2.
Crisis in Ukraine —
Protesters hold flags of the United States, Germany and Italy during a rally in Independence Square on March 2.
Emilio Morenatti/AP
People attend a morning prayer service at Independence Square on March 2.
Crisis in Ukraine —
People attend a morning prayer service at Independence Square on March 2.
LOUISA GOULIAMAKI/AFP/Getty Images
A soldier and a truck driver unload bread outside the Ukranian navy headquarters in Sevastopol on March 2.
Crisis in Ukraine —
A soldier and a truck driver unload bread outside the Ukranian navy headquarters in Sevastopol on March 2.
Andrew Lubimov/AP
Heavily armed troops, displaying no identifying insignia and who were mingling with local pro-Russian militants, stand guard outside a local government building in Simferopol on March 2.
Crisis in Ukraine —
Heavily armed troops, displaying no identifying insignia and who were mingling with local pro-Russian militants, stand guard outside a local government building in Simferopol on March 2.
Sean Gallup/Getty Images
A woman waits in front of unidentified men in military fatigues who were blocking a base of the Ukrainian frontier guard unit in Balaklava, Ukraine, on Saturday, March 1.
Crisis in Ukraine —
A woman waits in front of unidentified men in military fatigues who were blocking a base of the Ukrainian frontier guard unit in Balaklava, Ukraine, on Saturday, March 1.
VIKTOR DRACHEV/AFP/Getty Images
U.S. President Barack Obama, in the Oval Office of the White House, talks on the phone March 1 with Russian President Vladimir Putin.
Crisis in Ukraine —
U.S. President Barack Obama, in the Oval Office of the White House, talks on the phone March 1 with Russian President Vladimir Putin.
Pete Souza/White House Photo
Troops stand guard in Balaklava on March 1.
Crisis in Ukraine —
Troops stand guard in Balaklava on March 1.
Andrew Lubimov/AP
Heavily armed soldiers displaying no identifying insignia maintain watch in Simferopol on March 1.
Crisis in Ukraine —
Heavily armed soldiers displaying no identifying insignia maintain watch in Simferopol on March 1.
Sean Gallup/Getty Images
People gather around the coffin of a man who was killed during clashes with riot police in Independence Square.
Crisis in Ukraine —
People gather around the coffin of a man who was killed during clashes with riot police in Independence Square.
BULENT KILIC/AFP/Getty Images
Pro-Russian activists hold Russian flags during a rally in the center of Donetsk on March 1.
Crisis in Ukraine —
Pro-Russian activists hold Russian flags during a rally in the center of Donetsk on March 1.
Sergey Vaganov/AP
Pro-Russian activists clash with Maidan supporters as they storm the regional government building in Kharkiv, Ukraine, on March 1.
Crisis in Ukraine —
Pro-Russian activists clash with Maidan supporters as they storm the regional government building in Kharkiv, Ukraine, on March 1.
SERGEY BOBOK/AFP/Getty Images
A protester stands at a memorial March 1 for the people killed in clashes at Independence Square.
Crisis in Ukraine —
A protester stands at a memorial March 1 for the people killed in clashes at Independence Square.
Emilio Morenatti/AP
Armed men patrol outside the Simferopol International Airport on Friday, February 28.
Crisis in Ukraine —
Armed men patrol outside the Simferopol International Airport on Friday, February 28.
Sean Gallup/Getty Images
An image provided to CNN by a local resident shows Russian tanks on the move in Sevastopol.
Crisis in Ukraine —
An image provided to CNN by a local resident shows Russian tanks on the move in Sevastopol.
provided to cnn
Russian troops block a road February 28 toward the military airport in Sevastopol. The Russian Black Sea Fleet is based at the port city.
Crisis in Ukraine —
Russian troops block a road February 28 toward the military airport in Sevastopol. The Russian Black Sea Fleet is based at the port city.
Andrew Lubimov/AP
Armed men stand guard in front of a building near the Simferopol airport on February 28.
Crisis in Ukraine —
Armed men stand guard in front of a building near the Simferopol airport on February 28.
Bulent Doruk/Anadolu Agency/Getty Images
An armed man wearing no identifying insignia patrols outside Simferopol International Airport on February 28.
Crisis in Ukraine —
An armed man wearing no identifying insignia patrols outside Simferopol International Airport on February 28.
Sean Gallup/Getty Images
Police stand guard outside the Crimea regional parliament building Thursday, February 27, in Simferopol. Armed men seized the regional government administration building and parliament in Crimea.
Crisis in Ukraine —
Police stand guard outside the Crimea regional parliament building Thursday, February 27, in Simferopol. Armed men seized the regional government administration building and parliament in Crimea.
Sean Gallup/Getty Images
Police intervene as Russian supporters gather in front of the parliament building in Simferopol on February 27.
Crisis in Ukraine —
Police intervene as Russian supporters gather in front of the parliament building in Simferopol on February 27.
Bulent Doruk/Anadolu Agency/Getty Images
A man adds fuel to a fire at a barricade in Independence Square on February 27. Dozens of people were killed during clashes between security forces and protesters.
Crisis in Ukraine —
A man adds fuel to a fire at a barricade in Independence Square on February 27. Dozens of people were killed during clashes between security forces and protesters.
LOUISA GOULIAMAKI/AFP/Getty Images
Pro-Russia demonstrators wave Russian and Crimean flags in front of a local government building in Simferopol on February 27.
Crisis in Ukraine —
Pro-Russia demonstrators wave Russian and Crimean flags in front of a local government building in Simferopol on February 27.
Darko Vojinovic/AP
Barricades in front of a government building in Simferopol on February 27 hold a banner that reads: "Crimea Russia." There's a broad divide between those who support the pro-Western developments in Kiev and those who back Russia's continued influence in Crimea and across Ukraine.
Crisis in Ukraine —
Barricades in front of a government building in Simferopol on February 27 hold a banner that reads: "Crimea Russia." There's a broad divide between those who support the pro-Western developments in Kiev and those who back Russia's continued influence in Crimea and across Ukraine.
Darko Vojinovic/AP
Protesters stand in front of a government building in Simferopol on February 27. Tensions have simmered in the Crimea region since the ouster of Ukrainian President Viktor Yanukovych.
Crisis in Ukraine —
Protesters stand in front of a government building in Simferopol on February 27. Tensions have simmered in the Crimea region since the ouster of Ukrainian President Viktor Yanukovych.
Darko Vojinovic/AP
Protesters in support of the president's ouster rally in Independence Square, which has been the center of opposition, on Wednesday, February 26.
Crisis in Ukraine —
Protesters in support of the president's ouster rally in Independence Square, which has been the center of opposition, on Wednesday, February 26.
Marko Drobnjakovic/AP
Security forces stand guard during clashes between opposing sides in front of Crimea's parliament building in Simferopol on February 26.
Crisis in Ukraine —
Security forces stand guard during clashes between opposing sides in front of Crimea's parliament building in Simferopol on February 26.
Bulent Doruk/Anadolu Agency/Getty Images