President Ali Abdullah Saleh, a U.S. ally in the confrontation with al Qaeda, told army commanders on Tuesday that Yemen could descend into civil war because of efforts to stage what he called a "coup" against his rule.
Saleh has survived a civil war, tribal revolts and al Qaeda militants who have made skilful use of Yemen's poverty, tribal system and central government disfunction.
Here are some facts on al Qaeda in Yemen:
* WHAT IS AQAP?
-- Al Qaeda's Yemeni and Saudi wings merged in 2009 into a new group, al Qaeda in the Arabian Peninsula (AQAP), based in Yemen. They announced this three years after a counter-terrorism drive halted a 2003-06 armed al Qaeda campaign in Saudi Arabia.
-- AQAP's Yemeni leader, Nasser al-Wahayshi, was once a close associate of al Qaeda leader Osama bin Laden, whose father was born in Yemen, a neighbor of top oil exporter Saudi Arabia.
-- Yemen's foreign minister has said 300 AQAP militants might be in the country.
* THE RESPONSE:
-- AQAP claimed responsibility for an attempt on Christmas Day in 2009 to bomb a U.S.-bound passenger plane, and said it provided the explosive device used in the failed attack. The suspected bomber, a young Nigerian man, Umar Farouk Abdulmutallab, had visited Yemen and had been in contact with militants there.
-- Yemen declared open war on al Qaeda in January 2010 following the Christmas attack, stepping up air strikes targeting the group. But Sanaa has come under criticism from rights groups for the strikes, which also killed many civilians.
-- The United States and Saudi Arabia fear al Qaeda will exploit the instability in Yemen to make it a launch pad for more attacks. In 2010 Yemen said it would set up special forces in four of its provinces to fight al Qaeda.
-- Washington has authorized the CIA to kill or capture Anwar al-Awlaki, a U.S.-born cleric linked to AQAP. The group has threatened the United States with more attacks if he is harmed. Last month the United States announced it would spend $75 million to double the size of a special Yemeni counter-terrorism unit.
* RECENT AQAP OPERATIONS:
-- In August 2009, an AQAP suicide bomber tried to kill Prince Mohammed bin Nayef, who heads Saudi Arabia's anti-terrorism campaign and is a member of the royal family. The same year, al Qaeda carried out a suicide attack that killed four South Korean tourists in Yemen.
-- AQAP staged several attacks in Yemen in 2010, among them a suicide bombing aimed at the British ambassador in April. A rocket was fired at a British embassy vehicle in October.
-- The group also claimed responsibility for a foiled plot to send two air freight packages containing bombs to the United States in October 2010. The bombs were found on planes in Britain and Dubai. Last November AQAP vowed to "bleed" U.S. resources with small-scale attacks that are inexpensive but cost billions for the West to guard against.
-- Al Qaeda was active in Yemen long before the Saudi and Yemeni branches merged. Nearly a year before the September 11, 2001 attacks, it bombed the U.S. warship Cole in the southern port of Aden, killing 17 U.S. sailors. In 2002, an al Qaeda attack damaged a French supertanker in the Gulf of Aden.
-- In 2008, two suicide bombers set off blasts outside the heavily fortified U.S. embassy in Sanaa, killing 14 others. Islamic Jihad in Yemen, a group which analysts said was linked to al Qaeda, claimed responsibility.