Western embassies in Yemen heightened security measures on Thursday after increasingly bold attacks on foreigners by al Qaeda, even as the militant Islamists lost ground to an army offensive in the south, Alarabiya reported.
The government's offensive is the most concerted campaign against al-Qaeda in the Arabian Peninsula (AQAP) - seen by Washington as one of the group's most lethal wings - in nearly two years. The group has been blamed for deadly attacks against security forces, foreigners and oil and gas facilities.
Yemen has said its forces captured Azzan, the last major militant bastion targeted in an offensive that began 10 days ago.
Washington is keen to prevent any spillover of violence into neighboring oil power Saudi Arabia and to stop Yemen being used as a springboard to attack Western targets.
The European Union said on Thursday it had limited its presence in Yemen to essential staff, while France ordered its diplomats to restrict their movement.
"Like other diplomatic and international actors in Sanaa, we are limiting the presence to essential staff and reviewing our security measures," said Michael Mann, a spokesman for EU foreign policy chief Catherine Ashton.
On Wednesday, the United States announced a suspension of operations at its embassy.
Farhan Haq, a spokesman for the United Nations in New York, said the world body had no plans to move out of Yemen.
"To the contrary, (it) is determined to continue the implementation of its critical mandates in this country, including political, development and humanitarian. To enable the above, the U.N. is applying a variety of security risk management options," Haq said, without elaborating.
A spokeswoman for France's Foreign Ministry said its security alertness in Yemen was at maximum level but said the embassy remained open. On Monday, a French security agent was killed in Sanaa.
Britain's Foreign Office issued a new travel alert on Thursday, advising against all travel to Yemen and strongly urging British nationals to leave the Arabian Peninsula state.
The International Committee for the Red Cross, whose staff have been kidnapped and shot in recent years in Yemen, said it was reducing its exposure in Sanaa, where it described the security conditions as "extremely worrying, unpredictable."
"There are no private movements within the country except when people go to the airport for their (breaks)," Robert Mardini, head of ICRC operations for the Near and Middle East, told Reuters in Geneva.
Yemen scored a win against al Qaeda on Wednesday when Special Forces killed a militant suspected of masterminding attacks on Westerners, including the French agent on Monday.
Government troops captured the mountainous al-Mahfad area in Abyan province earlier this week, leaving Azzan in Shabwa province as the militants' main redoubt.
"An official military source in the third military region said that units of the armed forces and the security have entered ... Azzan," a statement on the Defence Ministry's website said. It also said security forces had killed a militant called Abu Musaab al-Kuwaiti.
The Yemeni defense minister told a crowd celebrating the capture of Azzan that the army's offensive against AQAP would continue, the state news agency Saba said.
Azzan, with a population of about 50,000, and some other towns in the south were declared Islamic emirates in 2011 by Ansar al-Sharia, an AQAP affiliate.
The army drove them out in 2012 but the militants have since rebuilt their presence, exploiting the Sanaa central government's traditionally weak hold over the region.
"We hope that the entrance of the army and the return of state authority to Azzan and other areas will be the end of the worry and turmoil that we've been living with for years," Azzan resident Mubarak Mahdi said.