(UPDATE) 24 Abu Sayyaf members killed in Sulu

ZAMBOANGA, Philippines (Xinhua) - At least 24 Abu Sayyaf Group (ASG) members have been killed and 27 injured as military operation against the group entered its fourth day in Sulu, military officers said on Saturday.

Combined military forces launched attacks on some 300 ASG members on Wednesday morning in the mountainous areas of Pakikul town in Sulu, and have gone on pursuit operations since then.

The firefights left two government soldiers dead and 26 others injured.

The military said police and marines have set up blocking operation and checkpoints to prevent the militants from slipping out of the operation zone in Patikul town.

The 400-strong ASG, founded in the early 1990s by Islamic extremists, is a violent Muslim terrorist group operating in the southern Philippines. The ASG is notorious for a series of kidnappings, bombings and even beheadings in southern Philippines over the past decades.