Moscow CNN  — 

Ukrainian lawmakers on Monday voted to introduce martial law in the border areas with Russia after it seized three Ukrainian navy ships and detained 24 sailors in a key waterway that holds strategic importance for both countries.

It’s the first time Ukraine has enacted martial law since the conflict with Russia began in 2014, indicating a major escalation in tensions between the two former Soviet Republics.

The law – which could give the government extraordinary powers over civil society – will start on November 28 and will last 30 days. In Parliament, 276 members voted for the motion.

Ukranian MPs speaking ahead of a parliamentary vote on whether to impose martial law in the country.

In a statement on Twitter, Ukraine President Petro Poroshenko said martial law would be introduced only in regions bordering Russia, or adjacent to regions where Russian troops are posted. That includes regions bordering the Azov and Black Seas and a portion of the border with Moldova’s Transnistria region, where Russian troops are stationed.

“This is where the blow can be struck,” Poroshenko said.

The Ukrainian government’s introduction of martial law follows a confrontation with Russia Sunday around a waterway linking the Azov Sea and the Black Sea.

Ukraine said two of its small gunboats and one tugboat were attacked by Russian naval forces Sunday after entering the Kerch Strait en route to the city of Mariupol.

Video of the incident released by Ukrainian officials appeared to show a Russian ship ramming the Ukrainian tugboat.

The incident provoked fury in Kiev, while Russia accused Ukraine of acting as the aggressor, calling the incident a “dangerous provocation” by Kiev.

During an emergency UN Security Council meeting to defuse rising tensions after Sunday’s confrontation, US Ambassador Nikki Haley called the incident “yet another reckless Russian escalation” and demanded that the Kremlin release the sailors.

“This is no way for a law-abiding, civilized nation to act,” Haley said, adding that it was an “outrageous violation” of Ukraine’s sovereignty.

“Impeding Ukraine’s lawful transit through the Kerch Strait is a violation under international law. It is an arrogant act that the international community must condemn and will never accept.”

US Ambassador to the United Nation Nikki Haley addresses the United Nations Security Council.

Secretary of State Mike Pompeo on Monday called for restraint by Ukraine and Russia following the incident.

“The United States condemns this aggressive Russian action. We call on Russia to return to Ukraine its vessels and detained crew members, and to respect Ukraine’s sovereignty and territorial integrity within its internationally recognized borders, extending to its territorial waters,” he said in a statement.

Ukraine’s navy said six of its sailors were injured in the incident on Sunday. It added that the tugboat and one of the gunboats were disabled and towed away by the Russian navy. The other gunboat was undamaged but was also seized by Russia, Ukraine said.

On Monday, Russia’s state news agency RIA reported that all 24 sailors aboard the three boats were detained by Russia, citing sources in Crimea’s security agencies. Three of the sailors were now in a hospital, it added.

The Kerch Strait – a shallow, narrow stretch of water just 2 to 3 miles wide at one point – connects the Azov Sea with the Black Sea and runs between the Crimean Peninsula and Russia. It is an important economic lifeline for Ukraine, as it allows its ships to access the Black Sea.

It’s also the closest point of access for Russia to Crimea, a peninsula Moscow annexed from Ukraine in 2014. A Russian-built bridge over the Kerch Strait was opened in May.

Russia has ‘no justification’ says NATO

Ahead of an extraordinary meeting of NATO-Ukraine ambassadors in Brussels late Monday, NATO Secretary General Jens Stoltenberg said Russia had “no justification” for seizing the Ukrainian ships.

“What we saw yesterday was very serious because we actually saw Russia use military force against Ukraine in an open and direct way,” Stoltenberg said, adding that NATO has increased its presence in the black sea region. “We have to show Russia that its actions have consequences.”

Earlier Monday, Stoltenberg pledged the alliance’s “full support for Ukraine’s territorial integrity” following a morning phone call with Ukrainian President Petro Poroshenko.

Similarly, European Union foreign affairs spokeswoman Maja Kocijancic condemned Russia at a press briefing on Monday. She called on Russia to “immediately release the vessels and the crew.”

European member states of the UN Security Council – including France, the Netherlands, Poland, Sweden and the UK – also called on Russia to restore freedom of passage at the Kerch Strait, in a statement.

On Monday, Kremlin spokesman Dmitry Peskov described the incident as a “dangerous provocation” by Kiev that required “special attention and special investigation,” the state news agency TASS reported.

Russia and Ukraine have been locked in long-simmering conflict since the annexation of the Black Sea peninsula of Crimea by Russia in 2014, and a war with Russian-backed separatists in the country’s east has claimed more than 10,000 lives.

Protesters gather outside the Russian embassy in Kiev on Sunday evening.

What happened

Ukraine and Russia offered conflicting accounts of the incident, each accusing the other of violating the laws of the sea. A 2003 agreement confirms the Azov Sea and the Kerch Strait as domestic waters of Russia and Ukraine.

Russia’s Federal Security Service (FSB) Border Service in Crimea reported that three Ukrainian warships had illegally entered Russia’s territorial waters and were carrying out dangerous maneuvers, according to Russian state news agency TASS.

TASS reported the three Ukrainian vessels were detained by Russian forces and that “weapons were used to force them to stop.”

“They did not respond to legitimate demands by the ships and boats of Russia’s FSB Border Guard Service escorting them to stop immediately and performed dangerous maneuvers,” the FSB said, according to TASS.

Three Ukrainian servicemen were wounded and received medical care from the Russians, TASS said.

The Ukrainian navy, on the other hand, said Russian border patrol vessels “carried out openly aggressive action” against the Ukrainian ships.

President Poroshenko’s office described the Russian action against the Ukrainian navy ships as “an act of aggression aimed at deliberately escalating the situation in the waters of the Sea of Azov and the Kerch Strait,” and called for international condemnation of Moscow and the imposition of new sanctions.

Ukrainian Interior Minister Arsen Avakov also tweeted video he claims shows the two ships colliding.

The video appears to be shot from on board a Russian vessel. A commander can be heard speaking Russian, swearing and ordering his crew to “slam him from the right,” “squeeze him” and finally warning those on board to “hold on” before the moment of impact.

It’s unclear how Avakov obtained the video. Similar clips were released by Russian state media but those did not show the actual collision.

In a post on Facebook, Russian Foreign Ministry spokeswoman Maria Zakharova said the incident had been devised to “divert attention from the internal problems that are ravaging Ukraine and blame the neighbor responsible for all of Ukraine’s troubles.”

In the wake of the incident, Russia temporarily closed off the strait. However, it has since been reopened for civilian ships, according to TASS.

Video from the scene showed a tanker blocking the waters under the bridge and fighter jets flying near the bridge.

A ship under the the Kerch bridge blocks the passage to the Kerch Strait near Kerch, Crimea, on Sunday.

On Sunday, Poroshenko convened a military cabinet emergency meeting and later tweeted he would appeal to Parliament to declare martial law. “There are no red lines” for Russia, he said. “We consider such actions categorically unacceptable. And this aggression has already led to consequences.”

Ukraine and the United States have been accusing Russia of interfering with international shipping in and out of the Kerch Strait for some months now.

Russian state media has reported the confrontation is a provocation orchestrated by Ukraine and others in America to disrupt the forthcoming meeting between Russian President Vladimir Putin and President Donald Trump at the G20 summit in Buenos Aires this week.