Twenty-one US embassies and consulates closed on Sunday.
The state department in Washington said the extended closures were “out of an abundance of caution”, and not a reaction to a new threat.
The UK said its embassy in Yemen would stay closed until the Muslim festival of Eid on Thursday.
The decision to close the embassies comes as the US government battles to defend recently disclosed surveillance programmes that have stirred deep privacy concerns.
Western governments are taking seriously the perceived threat from al-Qaeda in the Arabian Peninsula (AQAP), because the group has an established track record of highly innovative bomb plots. The bulk of its members are Yemeni militants with a local, Yemeni agenda, but the group has also attracted experienced al-Qaeda operatives from Saudi Arabia with more regional and international ambitions.
These include the elusive Saudi bomb-maker Ibrahim al-Asiri, who sent his brother to blow up a prince with a bomb concealed on, or possibly even inside, his body. Further plots from Yemen have followed, all thwarted, including the Nigerian Omar Farouk Abdulmutallab, who tried to detonate a bomb in his underpants on a flight to Detroit in 2009.
AQAP’s leaders have been intensively targeted by US drone strikes in recent years, but by hiding out in remote tribal areas, they have managed to remain largely beyond the reach of the authorities and to continue to plot attacks.
Security at US diplomatic facilities also remains a concern following last year’s attack on the US consulate in Benghazi, Libya, where the US ambassador and three other Americans were killed.
Source, BBC News