The Abu Sayyaf Group (ASG) is the most violent of the Islamic separatist groups operating in the southern Philippines and claims to promote an independent Islamic state in western Mindanao and the Sulu Archipelago. Split from the Moro National Liberation Front in the early 1990s, the group currently engages in kidnappings for ransom, bombings, assassinations, and extortion, and has ties to Jemaah Islamiya (JI). The ASG operates mainly in Basilan, Sulu, and Tawi-Tawi Provinces in the Sulu Archipelago, and has a presence on Mindanao. Members also occasionally travel to Manila.

The ASG has used terror both for financial profit and to promote its jihadist agenda. In April 2000, an ASG faction kidnapped 21 persons—including 10 Westerners—from a Malaysian resort, and, in May 2001, the ASG kidnapped three US citizens and 17 Filipinos from a resort in Palawan, Philippines, later murdering several of the hostages, including one US citizen. On 27 February 2004 members of Khadafi Janjalani’s faction bombed a ferry in Manila Bay, killing 116, and on 14 February 2005 they perpetrated simultaneous bombings in the cities of Manila, General Santos, and Davao, killing at least eight and injuring about 150. In 2006 ASG leader Janjalani’s faction relocated to Sulu, where it joined forces with local ASG supporters who are providing shelter to fugitive JI members from Indonesia.

In July 2007, the ASG and Moro Islamic Liberation Front engaged a force of Philippine marines on Basilan Island, killing 14. In November 2007, a motorcycle bomb exploded outside the Philippine Congress, killing a Congressman and three staff members. While there was no definitive claim of responsibility, three suspected ASG members were arrested during a subsequent raid on a safehouse. In January 2009, ASG kidnapped three International Red Cross workers in Sulu province, holding one of the hostages for six months.