Abu Sayyaf ( ; ; ,
ASG, ) is a militant
Islamist group based in and around
Jolo and
Basilan islands in the southwestern part of the Philippines, where for more than four decades,
Moro groups have been engaged in an
insurgency for an independent province in the country. The group is considered very violent, and was responsible for the
Philippines' worst terrorist attack, the bombing of Superferry 14 in 2004, which killed 116 people. The name of the group is derived from the Arabic ابو,
abu ("father of") and
sayyaf ("swordsmith"). As of 2012, the group was estimated to have between 200 and 400 members, down from 1250 in 2000. They use mostly
improvised explosive devices, mortars, and automatic rifles.