The southern Philippines has a long history of conflict, with armed groups including Muslim separatists, communists, clan militias and criminal groups all active in the area.
Three groups comprise the Muslim separatists - the Moro National Liberation Front (MNLF), the Moro Islamic Liberation Front (MILF) and the Abu Sayyaf. The MILF and the Abu Sayyaf are breakaway factions of the MNLF.
The communist insurgency, on the other hand, is propagated by the Communist Party of the Philippines' (CPP) military wing, the New People's Army (NPA).
Most of the conflict in the south is in the remote islands of central Mindanao, especially on Basilan and Jolo.
BBC News looks at the main rebel groups.