The U.S. State Department Tuesday ordered its non-essential staff to leave the country amid concerns of a possible terrorist attack.
- Formed by a 2009 merger of al-Qaida's Yemen and Saudi branches
- Led by Nasir al-Wahishi, former assistant to Osama bin Laden
- Established sanctuaries in Yemen, overrunning entire towns and villages
- Was behind unsuccessful underwear bomb plot on Christmas Day 2009
- Was behind foiled 2010 plot to send mail bombs hidden in toner cartridges to the US
U.S. media reports say intelligence agencies intercepted communications between al-Qaida leader Ayman al-Zawahri in Pakistan and the head of al-Qaida's branch in Yemen, Nasir al-Wuhayshi. The reports say al-Zawahri ordered the Yemen branch to carry out an attack as early as this past Sunday. But U.S. officials were unable to pinpoint the exact time and place of the possible attack.