Citing issues related to terrorism, three of the six members of the Gulf Cooperation Council have severed relations with Doha -- Saudi Arabia, Bahrain and the United Arab Emirates. The council is viewed as one of the most influential in the Middle East
Egypt, Yemen, Mauritius, Mauritania, the Maldives and Libya's eastern-based government have also suspended diplomatic relations.
The council is viewed as one of the most influential in the Middle East.
The kingdom, which has been ruled by the Saud family since its inception in 1932, is a close ally of the United States, but the relationship is often described as a "marriage of convenience
It is ruled by Crown Prince Mohammed bin Salman, who assumed power in early 2015.
Saudi Arabia maintains close ties with neighbor Bahrain and helped the Sunni monarchy there put down an Arab Spring uprising in 2011.
It is overwhelmingly Sunni, and Wahhabi -- or Salafi as it's also known -- branch of Sunni Islam is the official state-sponsored religion.
Saudi Arabia was a longtime supporter of Egyptian leader Hosni Mubarak before his overthrow in 2011. It did not support the successor government of Mohamed Morsy and the Muslim Brotherhood.
After Morsy's overthrow in 2013, Saudi Arabia returned its support to new President Abdel Fattah el-Sisi. It severed ties with longtime foe Iran after January 2016 attack on the Saudi Embassy in Tehran.
Bahrain, an archipelago of 33 islands off the coast of Saudi Arabia, is a constitutional monarchy with an elected legislative assembly that has been ruled by the al Khalifa family since 1783.
A former British protectorate, the country gained full independence in 1971.
For centuries, pearls were Bahrain's biggest export and its main source of income.
In the early 1930s, though, Bahrain became the first Gulf state to find a sizable deposit of crude oil, a discovery that boosted its economy and accelerated its modernization
Bahrain is home to the US Fifth Fleet and is a key ally of the United States.
While the majority of its citizens are Shia, it is ruled by the Sunni Khalifa family.
Bahrain's ruling class weathered an uprising in 2011 during the Arab Spring, largely due to Saudi support, including troops.
The Obama administration signed off on the sale of F-16 fighter jets last year but included conditions tied to the human rights record of Bahrain.
The Trump administration's State Department has signaled its intentions to move forward on the sale without the conditions.
The country saw upheavals during the Arab Spring when Mubarak, a key Saudi supporter, was forced to step down as president.
Morsy swept into power, damaging relations with Saudi Arabia, but he was deposed in a 2013 coup.
The election of Egypt's army chief, Sisi,
returned Saudi support to its North African ally.
Egypt has been a longtime US ally, but the bloody, military-backed coup in 2013 led to a moratorium on material support.
US-Egyptian relations normalized in 2015 when President Barack Obama ended the freeze on weapons shipments
to the country.
Qatar is home to up to 200,000
Egyptian migrant workers. In the past, the Egyptian government hasn't joined diplomatic action against Qatar due to the risk of repercussions
relating to Egyptian nationals working in that Gulf state.
United Arab Emirates
In 1971, six Arab states -- Dubai, Abu Dhabi, Sharjah, Ajman, Al Fujayrah and Umm al Qaywayn -- gained independence from the UK and formed a federation known as the United Arab Emirates. They were joined in 1972 by Ra's al Khaymah.
Majority Sunni, the country is ruled by a president chosen by the seven members of the Federal Supreme Council. Khalifa bin Zayid Al-Nuhayyan is the incumbent and has ruled since 2004. There is a small Shia minority.
The UAE has largely avoided the unrest that the Arab Spring wrought on much of the region.
It has diversified significantly from the oil and natural gas wealth that brought it prominence and raised standards of living.
It's the single largest market for US exports in the Middle East, and American companies have invested $15.6 billion there.
More than 1,000 American firms operate in the UAE.
Part of the Arab League, the Republic of Yemen was created in 1990 from the unification of the Yemen Arab Republic in the north and the People's Democratic Republic of Yemen in the south.
Mired in a civil war, the country is strongly supported militarily by Saudi Arabia, its neighbor to the north.
The two-year long conflict, which has seen around 8,000 fatalities and more than 50,000 injuries, is essentially a proxy war between Saudi Arabia and its main regional rival, Iran, which is arming the opposition Houthi rebels.
In October 2000, the USS Cole, at anchor in Aden, was bombed by al Qaeda, killing 17 US sailors, and eight years later a terrorist attack on the US Embassy in Sanaa left 16 dead, including six attackers.
Maldives, a chain of islands in the Indian Ocean, claimed Qatar supports "activities that encourage terrorism and extremism."
The Sunni Muslim nation said it "has always pursued a policy of promoting peace and stability in the Middle East."
Its economy relies greatly on tourism, and the country is facing challenges from the rising of sea levels.
It is also a destination for people subjected to forced labor and sex trafficking, the CIA World Factbook said.
The West African country of Mauritania announced it would sever all diplomatic ties with Qatar, due to what it claimed was the country's policy of "supporting terrorist organizations and promoting extremist ideas."
An Islamic Republic, Mauritania is a majority Muslim country, with most inhabitants adhering to the Sunni denomination. It is one of only seven remaining countries where the expression of atheist views or defection from the official religion can result in the death penalty.
Despite being rich in natural resources, including iron ore, gold, copper, gypsum, the country is among the region's poorest, with half the population still agriculture or livestock dependent, according to the CIA World Factbook.
It was described in a 2012 CNN feature as "slavery's last stronghold
" due to the high percentage of its population -- between 10% to 20% -- thought to be enslaved.
Since gaining independence from the UK in 1968, Mauritius -- a small island nation in the Indian Ocean -- has developed as a tourist economy, known for its luxury spas and beaches.
The office of the country's Vice Prime Minister announced that it was "fully committed to supporting the actions of Saudi Arabia and other countries in their efforts to eradicate threats against international peace" and pending further development, has "decided not to entertain any further relations with Qatar."
Home to a multi-ethnic, majority Hindu population, the country has signed a number of major trade deals with foreign governments and investors in recent years, most notably India
Libya's eastern-based government announced it would cut off all diplomatic ties with Qatar, due to "repeated attacks by Qatar on the dignity of the Libyan people after the 17 February revolution."
In 2011, protests spread through the country, igniting an eight month long civil war.
The eastern-based government, centered in the city of Tobruk, has little authority within Libya, however, and has no diplomatic representation in Doha.
The eastern-based government is aligned with the powerful military commander Khalifa Haftar, and rejects the UN-backed internationally recognized government in the capital, Tripoli.
Qatar's fossil fuel wealth has made it the world's highest per-capita income country, according to the CIA World Factbook.
It also boasts the lowest unemployment for any country.
The United States maintains its biggest concentration of military personnel in the Middle East
at Qatar's Al Udeid Air Base. It's home to some 11,000 US military personnel.
Qatar is scheduled to host the World Cup soccer tournament
in 2022 and is the home of Al Jazeera, the influential news network.
Like Bahrain, Qatar is a former British protectorate, gaining full independence in 1971.
From the 1950s onward, the country began to transform itself through its oil and natural gas resources, and since a bloodless coup in 1995, and subsequent political reform, has directed much of this wealth into diversified investment. Now just over half of its gross domestic product comes from non-fossil fuel sources.
Former ruler Hamad bin Khalifa Al Thani, who overthrew his father, peacefully transferred power to his son, Emir Tamim bin Hamad, in 2013, who, until recently, oversaw improving relations with regional neighbors, including Bahrain, Saudi Arabia and the UAE.