Qatar hosts the largest USA air base in the region, which is crucial to operations against Islamic State group jihadis, and is set to host the 2022 football World Cup. A new port, a medical zone, a metro project and eight stadiums are just some of the major construction projects underway.
Qatar is the biggest supplier of liquefied natural gas (LNG) and a major seller of condensate - a low-density liquid fuel derived from natural gas.
Experts say Qatar's insistence that it is one of the most stable countries in the Middle East was a key reason why it was controversially chosen.
The four countries began withdrawing their diplomatic staff from Qatar as regional airlines announced they'd suspend service to its capital, Doha. It was unclear whether the suspension would be extended.
Saudi Arabia said Qatari troops in the Saudi-led coalition fighting Houthi rebels in Yemen would be recalled home.
Trump Admin. to return Russian compounds in US
Kremlin aide Yury Ushakov told the Sputnik news agency that Russian Federation had the right to take back the St. The State Department separately ejected 35 diplomatic personnel suspected of being intelligence operatives.
He encouraged Qatar and its neighbors to "sit down together", adding that Washington was ready for "any role that we can play" in helping to overcome divisions.
Iran, Turkey and the US have called on all sides to resolve their differences, with US Secretary of State, Rex Tillerson, pressing for dialogue. Last month, Qatar's state news media published comments attributed to the emir, Sheikh Tamim bin Hamad al-Thani, referring to tension with Washington over Iran policy and saying Mr. Trump might not be in power for long.
Robert Gates, the former U.S. defence secretary was quoted by Financial Times as saying Tuesday that the United States should demand that Doha should be more aggressive in shutting down terror financing, or risk a downgrading of the US's military presence in the country.
Doha denied the comments and said it had been the victim of a "shameful cybercrime".
State-linked Saudi media launched an aggressive campaign accusing Qatar of supporting terrorist groups like al-Qaida and the Islamic State, destabilizing the region and stabbing its allies in the back.
Libya alleged that Qatar interfered in its domestic affairs. And though the comments appeared on Qatar's official website, Qatari authorities said the website has hacked and the comments fabricated.