WASHINGTON // The US State Department has ordered its embassy in Yemen to be evacuated as a result of the threat by Al Qaeda that has triggered temporary shutdowns of 19 American diplomatic posts across the Middle East and Africa.
A statement issued today said the department has ordered the departure of non-emergency US government personnel from Yemen "due to the continued potential for terrorist attacks".
The travel warning said US citizens currently in Yemen should depart and calls the security threat level in Yemen "extremely high".
"As staff levels at the Embassy are restricted, our ability to assist US citizens in an emergency and provide routine consular services remains limited and may be further constrained by the fluid security situation," the travel warning said.
The US embassy is located in Sanaa, the capital of Yemen.
The UK followed and said it had withdrawn all staff from its embassy in Yemen.
"Due to increased security concerns, all staff in our Yemen embassy have been temporarily withdrawn, and the embassy will remain closed until staff are able to return," a statement from the Foreign Office said.
A US intelligence official and a Middle East diplomat told The Associated Press that the current shutdown was instigated by an intercepted secret message between Al Qaeda chief Ayman Al Zawahri and his deputy in Yemen about plans for a major terror attack.
The New York Times said in its online edition that the electronic communications last week revealed that Zawahiri had ordered Nasser Al Wuhayshi, the head of Al Qaeda in the Arabian Peninsula, to carry out an attack as early as this past Sunday.
CNN meanwhile reported that Zawahiri told Wuhayshi to "do something," causing officials in both Washington and Yemen to fear an attack was imminent.
As a result, roughly two dozen US diplomatic posts were shuttered across the Middle East Sunday, and the State Department, insisting it was acting "out of an abundance of caution," said 19 would remain shut through Saturday.
Al-Qaeda in the Arabian Peninsula (AQAP) is seen as the terror network's most capable franchise following the decimation of its core leadership in Afghanistan and Pakistan in recent years.
The Yemen-based group has attempted a number of attacks on US soil, including a bid to bring down a passenger plane in 2009 by a man wearing explosives in his underwear and a failed plot to send bombs concealed in printers.
The United States in turn has launched scores of drone strikes in Yemen, where the militant group thrives in vast, lawless areas largely outside of the government's control.
A drone strike in Yemen early Tuesday struck a vehicle, killing four suspected Al Qaeda militants "in a ball of fire,", a tribal source told AFP, adding that all four men were Yemeni.
It was not immediately clear if the strike was linked to the global alert. US officials rarely speak about the drone program.
Several US allies, including Britain, France, Germany and Norway have also announced closures of some of their missions in the region.
The US closure list includes 15 embassies or consulates that were shut on Sunday -- the fifteenth anniversary of Al Qaeda's attacks on US embassies in East Africa -- as well as four additional posts.
Lawmakers in Washington described the threat level as very serious, with some invoking the September 11, 2001 attacks.
Michael McCaul, chairman of the House Homeland Security Committee, dubbed the intelligence "probably one of the most specific and credible threats I've seen, perhaps, since 9/11."