Nov 8 Here are some facts on the Yemen-based branch of al Qaeda, which has claimed responsibility for a foiled plot to send explosive parcels to the United States in October. The group made the claim in a Nov. 5 message posted on Islamist Internet forums.
* Al Qaeda's Yemeni and Saudi wings merged in 2009 into a new group, al Qaeda in the Arabian Peninsula (AQAP), based in Yemen. A Saudi counter-terrorism drive halted an armed campaign in Saudi Arabia by al Qaeda from 2003 to 2006.
* 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 neighbour of top oil exporter Saudi Arabia.
* AQAP has carried out attacks against Westerners and seeks the fall of the U.S.-allied Saudi royal family. Yemen's foreign minister has said 300 AQAP militants might be in the country.
* AQAP claimed responsibility for an attempt to bomb a U.S.-bound passenger plane on Dec. 25, 2009, 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 Day 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.
* On Nov. 5, the militant group claimed responsibility for for a foiled plot to send explosive parcels to the United States -- two parcel bombs were intercepted on cargo planes in Britain and Dubai. It also claimed responsibility for the September crash of a UPS (UPS.N) plane in Dubai, in which two crew members died. However, the United Arab Emirates' civil aviation authority said on Oct. 31 that there was no evidence of an explosive device aboard the jet.
* The United States and Saudi Arabia fear al Qaeda will exploit instability in Yemen -- which is also trying to cement a truce with Shi'ite rebels in the north and quell separatist unrest in the south -- to make it a launch pad for more attacks.
* U.S. officials have said the Pentagon is boosting military assistance to Yemen's special operations forces to lead an offensive targeting AQAP.
* AQAP has 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.
* 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 Saudi royal family. The same year, al Qaeda also carried out a suicide attack that killed four South Korean tourists in Yemen.
* As well as hitting Western targets, AQAP has retaliated against Yemeni forces trying to crack down on the group. It has claimed attacks on troops this year, including one on a southern checkpoint in August in which eight soldiers were killed.
* Al Qaeda was active in Yemen long before the Saudi and Yemeni branches merged. Nearly a year before the Sept. 11, 2001 attacks, it bombed the U.S. warship Cole in October 2000 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 16 people, including the attackers. Islamic Jihad in Yemen, a group which analysts said was linked to al Qaeda, claimed responsibility.
* U.S. officials say Washington has authorised 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 should he be harmed.
Our top photos from the past week.