The American and British embassies in Sanaa remained shut for a second day following indications that an Al-Qaeda branch linked to a botched US airliner bombing is targeting Western interests.
Yemeni authorities meanwhile have tightened security measures at and around the capital's airport, as well as around several embassies, an AFP correspondent said.
New checkpoints were installed along the airport road while security measures were reinforced around the missions of Britain, Germany, Saudi Arabia and the United States.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
A security officer at the US mission in Sanaa told AFP telephonically that the embassy was still closed, without providing further information.
A Western diplomat meanwhile said that the British embassy remained shut.
The US embassy on Sunday announced closing in response to "ongoing threats by Al-Qaeda in the Arabian Peninsula (AQAP) to attack American interests in Yemen."
Britain followed suit, with a spokeswoman for the Foreign Office in London confirming its Sanaa embassy had been closed "for security reasons."
US President Barack Obama has accused the Yemen-based AQAP of arming and training a Nigerian accused of trying to blow up a Detroit-bound Northwest Airlines jet on Christmas Day.
AQAP claimed responsibility for the failed attack and called for strikes on embassies in Yemen.
Obama's counter-terrorism advisor John Brennan said Sunday there were indications of an Al-Qaeda plot to launch attacks in Yemen.
"There are indications that Al-Qaeda is planning to carry out an attack against (a) target inside of Sanaa, possibly our embassy," he said.
Britain followed suit closing its embassy, while Spain decided to restrict public access to its Sanaa embassy.
Fears grew after AQAP urged Muslims to attack Western targets in the impoverished Arabian Peninsula country after claiming the attack.
"We call upon every Muslim who cares about his religion and doctrine to assist in expelling the apostasies from the Arabian Peninsula, by killing every crusader who works at their embassies or other places (and) declare an all-out war against every crusader on (the Prophet) Mohammed's peninsula on land, air and sea," it said in a statement.
