MANILA (Updated) — Philippine military officials said at least seven troops were killed in clashes with Abu Sayyaf militants in the province of Sulu on Thursday.

Military spokesman Lt. Col. Ramon Zagala said government forces assaulted a group of fighters from the Abu Sayyaf group, sparking a gunbattle that killed a marine after dawn in the jungles off Patikul town in Sulu, a predominantly Muslim province where the militants have been active for years.

Zagala added army reinforcements were hit by mortar fire 10 minutes later, killing six soldiers and wounding 13 others near the scene of the initial battle. He said that three of the wounded were in serious condition and airlifted by air force helicopters to a military hospital in southern Zamboanga city.

He said there was no immediate report of casualties among the militants, who have been holding a number of hostages in Sulu, including two European bird watchers who were kidnapped two years ago.

The Abu Sayyaf, which is blacklisted by Washington as a terrorist organization, was organized in the early 1990s in Basilan province, near Sulu. With an unwieldy collective of preachers and outlaws, it vowed to wage jihad, or holy war, but lost its key leaders early in combat, sending it on a violent path of extremism and criminality.

About 300 armed Abu Sayyaf fighters remain in Sulu, Basilan and outlying islands, surviving mostly on kidnappings for ransom and extortion. Although its leadership and members have been crippled by years of a US-backed Philippine anti-terrorism campaign, the Abu Sayyaf has endured and remains a worrisome national security threat. (AP)