The decision comes after Washington threatened to respond to an Iranian government crackdown on protests while Tehran has said it would strike US military and shipping assets in the event of a new attack.

The measure was taken “in response to the current regional tensions”, Qatar’s International Media Office said in a statement.

“Qatar continues to implement all necessary measures to safeguard the security and safety… including actions related to the protection of critical infrastructure and military facilities,” it added.

A diplomatic source told AFP earlier that a number of personnel were asked to leave the base by Wednesday evening.

A second source confirmed the information, also on condition of anonymity.

The US embassy in Qatar declined to comment on personnel movement at Al Udeid.

In June, Iran targeted the US’ Al Udeid military base in Qatar in response to earlier American strikes on Iranian nuclear facilities.

Ali Shamkhani, a senior adviser to Iran’s supreme leader Ayatollah Ali Khamenei, warned US President Donald Trump today that the strike on the base had demonstrated “Iran’s will and capability to respond to any attack”.

Doha was able to leverage the unprecedented attack on its soil to help deliver a speedy truce between Washington and Tehran.

Washington has repeatedly said the US is considering air strikes on Iran to stop a crackdown on protesters.

Trump on Tuesday said in a CBS News interview that the US would act if Iran began hanging protesters.

Iranian authorities called the American warnings a “pretext for military intervention”.

Mass protests in Iran since Thursday have posed one of the biggest challenges to the clerical leadership since the 1979 Islamic revolution ousted the shah.

Norway-based NGO Iran Human Rights said it had confirmed 734 people killed during the protests, including nine minors, but warned the death toll was likely far higher.

“The real number of those killed is likely in the thousands,” IHR’s director Mahmood Amiry-Moghaddam said.