Civil war and lawlessness have turned Yemen into an alternative base for al-Qaeda, which U.S. officials say has been largely pushed out of Afghanistan and is under military pressure from Pakistan. Between 200 and 300 al-Qaeda fighters are believed to be operating in Yemen, including foreign veterans of the wars in Iraq and Afghanistan. Following is a timeline tracing al-Qaeda activity in Yemen since 2000.
Oct. 12, 2000 The bombing of the destroyer USS Cole in Aden harbour kills 17 sailors and blows a hole in the ship's hull.
Oct. 6, 2002 An explosion damages the French supertanker Limburg in the Gulf of Aden in an attack for which five al-Qaeda-linked Yemenis are later convicted.
July 2, 2007 Seven Spanish tourists are killed when a car bomb hits their convoy in the eastern province of Marib.
Jan. 18, 2008 Gunmen fire on a tourist group in Hadramaut, killing two Belgian women and their two Yemeni drivers.
Sept. 17, 2008 Two suicide car bombers attack the heavily fortified U.S. embassy complex in Sanaa, killing 16 people. Washington says the attack bears "all the hallmarks" of al-Qaeda.
January, 2009 Al-Qaeda's Yemeni and Saudi wings announce they have merged into a new group called al-Qaeda in the Arabian Peninsula led by Nasser al-Wahayshi, former Yemeni aide to Osama bin Laden.
June, 2009 The bodies of three kidnapped foreign women - two Germans and a South Korean - are found in the northern province of Saada. Six other foreigners remain missing. No group claims responsibility, though AQAP is suspected.
August 27, 2009 Abdullah al-Asiri, an al-Qaeda suicide bomber posing as a repentant militant, is flown from Yemen to Saudi Arabia, where he tries to kill the kingdom's anti-terrorism chief, Prince Mohammed bin Nayef, in the first such attack on a Saudi royal.
Nov. 3, 2009 Al-Qaeda claims the killing of seven Yemeni security officials in an ambush near the Saudi border.
Dec. 24, 2009 Yemen says 30 al-Qaeda militants are killed in air strikes in the eastern province of Shabwa. A security official says Mr. Wahayshi, his Saudi deputy, Saeed al-Shehri, and U.S.-born cleric Anwar al-Awlaki are among the dead. There is no confirmation.
Dec. 28, 2009 AQAP claims responsibility for the failed bombing of a Detroit-bound U.S. airliner on Christmas Day.
Jan. 1, 2010 Sheik Mukhtar Robow Abuu Mansuur, a leader of the Somali Islamist militia al-Shabaab, says his group is ready to send reinforcements to AQAP should the United States attack its bases in Yemen.
Jan. 5, 2010 U.S. President Barack Obama suspends the transfer of prisoners held at Guantanamo Bay to Yemen after revelations that former detainees have joined AQAP. Of the 198 prisoners still held at Guantanamo, about 90 are Yemeni. Among the senior leadership of AQAP are two Saudi militants released from Guantanamo several years ago.
Jan. 27, 2010 An international conference being convened by Britain with the United States and other nations will explore ways of fighting al-Qaeda in Yemen.