Qatar has temporarily closed its airspace after the US and the UK told their citizens in the country to shelter in place "until further notice".

The US embassy in Qatar suggested in a notice online that Americans do so "out of an abundance of caution". The UK government said it was issuing its warning in response to the US alert.

The warnings come after the State Department told US citizens in international locations to "exercise increased caution," after the US bombed three nuclear sites in Iran on Saturday. Iran has threatened to retaliate.

The BBC understands that there is "a credible threat" to the US-run Coalition Air Operations Centre at Al-Udaid in Qatar.

In a statement, Qatar's Ministry of Foreign Affairs said the closure of its airspace was to ensure the safety of residents and visitors.

In a separate statement in response to the embassy notice, the foreign ministry said the warning did "not necessarily reflect the existence of specific threats".

"The security situation in the country is stable," the statement said, adding that "the relevant authorities are closely monitoring the situation and are ready to take all necessary measures to ensure the safety of citizens, residents, and visitors".

Qatar is home to the largest US military base in the Middle East, Al Udeid Air Base. About 8,000 US citizens live there, according to the State Department.

It is also home to US CENTCOM's headquarters for all its air operations in the Middle East, where British military personnel also serve on rotation.

The US has about 40,000 troops stationed in the Middle East.

Flight tracking websites show planes diverting to other airports following the closure of Qatari airspace. According to Flightradar24, there are 100 flights bound for Doha.

Hamad International Airport is one of the world's top 10 busiest airports on international traffic with around 140,000 passengers passing through per day.

Advice for British nationals in Qatar may be updated "over the course of the next few days", the Foreign Secretary David Lammy has said.

He told Parliament: "This is an ongoing and fast-moving situation." He added that the government would keep advice "under close review and there may need to be further updates over the course of the next few days".

The message from the US Embassy was followed by warnings from other groups in Qatar, including several universities that asked students to go home.

Bilateral relations between the US and Qatar are "strong", according to the State Department, which says Qatar has helped play a financial, political and military role in dealing with turmoil in the region.