"The security situation in Yemen has continued to deteriorate over recent days," Tobias Ellwood, the British Foreign Office's official responsible for the Middle East, said in a statement on Wednesday.

Ellwood added that all staff had left early on Wednesday morning and asked all British nationals to "leave immediately."

France followed suit, saying its Sanaa embassy would close as of Friday. In a statement on its website, the French embassy told French citizens to leave the country "as soon as possible."

Yemen has been plagued by unrest for months, with Shiite Houthi rebels besieging the capital before taking control last week. The Sunni al Qaeda in the Arabian Peninsula (AQAP) has vowed to destroy its Shiite rivals.

On Tuesday, the US announced that it would temporarily close its embassy in Yemen for the second time in a month. US officials said the embassy closure would not affect counter-terrorism operations against al Qaeda's Yemeni branch, which America views as the organization's most dangerous branch.

On January 25, US President Barack Obama had vowed that the US would not let up in its efforts to fight al Qaeda in Yemen despite the unrest.

But the US embassy closure will complicate the CIA's operations in Yemen, intelligence officials have acknowledged. Although they 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.

ng/sms (Reuters, AP)