Yemeni security on high alert after embassy closures

Security is especially tight in Yemen\'s capital Sanaa Yemeni security forces are on high alert amid fears of an imminent attack by global Islamist militant organisation al-Qaeda .
It comes after the US and Britain withdrew embassy staff and urged their citizens to leave the country.
Security has been deployed outside the American, British, French and German embassies in Sanaa, to prevent any potential terror attacks that could target them in days leading up the Islamic festival of Eid-al-Fitr.
The Yemeni interior ministry said it had devised a plan to protect state institutions and was trying to verify reports that a number of militants have entered Sanaa over the last few days.
The US on Tuesday ordered Americans to leave Yemen \"immediately\" after hearing electronic intercepts from al-Qaeda leader Ayman al-Zawahiri.
Zawahiri reportedly told Nasser al-Wuhayshi, the leader al-Qaeda in the Arab Peninsula (AQAP) to \"do something,\" CNN reported. The New York Times said Zawahiri had ordered AQAP to carry out an attack as early as last Sunday.
The State Department said it had pulled all non-essential personnel from Yemen, and the Pentagon said the US Air Force had flown staffers out early Tuesday.
\"We are concerned about a threat stream indicating the potential for terrorist attacks against US persons or facilities overseas, especially emanating from the Arabian Peninsula,\" State Department spokeswoman Jen Psaki said in a statement.
\"As such, the department is taking appropriate steps to protect our employees, including local employees and visitors to our facilities.\"
Pentagon spokesman George Little said defence department personnel remain \"on the ground in Yemen to support the US State Department and monitor the security situation.\"
Britain meanwhile announced the temporary withdrawal of all personnel from its embassy in Yemen, saying it would remain closed \"until staff are able to return.\"
AQAP is seen as the terror network\'s most capable franchise following the decimation of its core leadership in Afghanistan and Pakistan in recent years.
The Yemen-based group has attempted a number of attacks on US soil, including a bid to bring down a passenger plane in 2009 by a man wearing explosives in his underwear and a failed plot to send bombs concealed in printers.
The United States in turn has launched scores of drone strikes in Yemen, where the militant group thrives in vast, lawless areas largely outside the government\'s control.
A drone strike in Yemen Tuesday struck a vehicle, killing four suspected al-Qaeda militants \"in a ball of fire,\" a tribal source told AFP.
One of the four was on a list released by Yemeni authorities of 25 al-Qaeda operatives suspected of plotting attacks to coincide with the end of the Muslim holy month of Ramadan later this week, according to the source.