The United States and Britain have temporarily suspended operations of their embassies in Yemen because of the political crisis and security concerns following the takeover of much of the country by Shiite rebels.
Britain withdrew its staff from its embassy in Yemen and temporarily suspended operations there over security concerns, the Foreign Office said on Wednesday, a day after the United States shut its embassy.
"The security situation in Yemen has continued to deteriorate over recent days," Minister for the Middle East Tobias Ellwood said in a statement.
State authority in Yemen has unravelled since a Shi'ite Muslim militia formally seized power last week and the Sunni al-Qaeda in the Arabian Peninsula (AQAP) group has sworn to destroy it, stoking fears of sectarian civil war.
"Our Ambassador and diplomatic staff have left Yemen this morning and will return to the UK," Ellwood said.
Earlier, the US State Department confirmed late on Tuesday that it has closed its embassy in Yemen and evacuated its staff amid the continued unrest.
The department announced it had suspended operations at the embassy in Sanaa and relocated its remaining diplomatic personnel "due to the ongoing political instability and the uncertain security situation." The embassy had been operating with only a skeleton staff for some weeks amid deteriorating conditions.
Yemen has been in crisis for months, with Iran-linked Shiite Houthi rebels besieging the capital and then taking control. Earlier on Tuesday, US officials said the embassy closure would not affect counterterrorism operations against al-Qaida's Yemen branch.
"The United States remains firmly committed to supporting all Yemenis who continue to work toward a peaceful, prosperous and unified Yemen," State Department spokeswoman Jen Psaki said. "We will explore options for a return to Sanaa when the situation on the ground improves."
The State Department also issued a travel warning advising US citizens to defer travel to Yemen and urging US citizens currently living in Yemen to depart.
Although operations against al-Qaida's Yemen affiliate will continue, the closure of the embassy will be seen as a blow to the Obama administration, which has held up its partnership with ousted Yemeni President Abed Rabbo Mansour Hadi's government as a model for his strategy in combatting terrorism, particularly in unstable countries.
"Yemen has never been a perfect democracy or an island of stability," President Barack Obama said late last month as conditions in the capital of Sanaa became worse. "What I've said is, is that our efforts to go after terrorist networks inside of Yemen without an occupying US army, but rather by partnering and intelligence-sharing with that local government, is the approach that we're going to need to take."
The US embassy closure will also complicate the CIA's operations in Yemen, US intelligence officials acknowledge. Although CIA officers could continue to work out of US military installations, many intelligence operations are run from embassies, and the CIA lost visibility on Syria when that embassy was evacuated in 2012.
The CIA's main role in Yemen is to gather intelligence about members of al-Qaida in the Arabian Peninsula and occasionally kill them with drone strikes. Both the CIA and the military's Joint Special Operations Command run separate drone killing programs in Yemen, though the CIA has conducted the majority of the strikes, U.S. officials have said.
(With inputs from Reuters and AP)