At least five soldiers were killed and dozens others were wounded during a firefight with pro-Islamic State (IS) Abu Sayyaf gunmen in the southern Philippines, military officials said Saturday.

The clash ensued around 4:10 p.m. Friday in the village of Lianga, Patikul, a remote town on Sulu island, when Army’s 41st Battalion conducting patrols encountered nearly 50 heavily armed Abu Sayyaf group, regional military spokesman Col. Gerry Besana said.

Besana said the fighting that lasted for an hour and thirty minutes was intense that left them five soldiers dead and 23 others wounded.

“The enemies were holding hostages at the time of encounter,” Besana said, adding the militants were led by Commander Almuder Yaddah.

The remains of slain soldiers were airlifted to Zamboanga City, while the wounded soldiers were brought to a military hospital in Sulu for treatment.

The Abu Sayyaf, or Bearers of the Sword, is the most violent of several Muslim rebel factions in the southern Philippines. It is responsible for the worst attacks in the country, including a ferry bombing in Manila Bay that killed more than 100 people in 2004.

The militants are still holding 12 hostages, including three Indonesians, one Vietnamese, one Dutch national and seven Filipinos. DMS