Article: In January 2002, the U.S. sent more than 1,200 troops (later raised to 2,000) to assist the Armed Forces of the Philippines in combating terrorist groups linked to al-Qaida, such as Abu Sayyaf, under Operation Enduring Freedom - Philippines. Operations have taken place mostly in the Sulu Archipelago, where terrorists and other groups are active. The majority of troops provide logistics. However, there are special forces troops that are training and assisting in combat operations against the terrorist groups.

Question: What was the name of the Philippine terrorist group the US was sent to help combat?
Abu Sayyaf