MANILA, Philippines (AP) — Philippine troops, backed by airstrikes and artillery fire, killed 11 suspected Islamic militants near a hinterland village in the country’s south, authorities said Saturday, in one of the military’s bloodiest anti-insurgency offensives this year.

The military launched the offensive Friday after receiving intelligence about the whereabouts of suspected leaders and armed followers of the Dawla Islamiyah and the Bangsamoro Islamic Freedom Fighters, or the BIFF, groups near the village of Tuwayan in southern Datu Hofer town in Maguindanao province, military officials said.

Army Maj. Saber Balogan, a regional military official, said government forces recovered 11 bodies of suspected militants after more than three hours of fighting.

Troops also recovered Seven M16 and M14 assault rifles, rocket-propelled grenades and five homemade bombs from the scene, he said, adding that there were no military casualties.

The Associated Press saw a confidential initial government report about the military operation, which stated that two Philippine air force fighter planes dropped eight 500-pound bombs in the hinterland areas where the militants were spotted. Two military helicopters further targeted the militants.

Army troops were deployed after to the battle scene, military officials said.

This came after 13 armed militants belonging to the Dawla Islamiyah surrendered with their firearms to the military in the south, Maj. Gen. Alex Rillera, a regional military commander said.

It was not immediately clear if the militants provided information that helped the military decide to launch Friday’s assault.

“This is the good side of coming out and laying down your guns; You can now live peacefully with your loved ones,” Rillera told the militants, who surrendered in a ceremony on Thursday in South Cotabato province adjacent to Maguindanao province, where the military offensive was carried out the following day.

After decades of debilitating armed hostilities, the Philippine government signed a 2014 peace pact with the largest Muslim separatist group, the Moro Islamic Liberation Front, in the south of the largely Catholic nation. That considerably eased armed insurgency-related clashes and violence in the south.

However, smaller Muslim separatist groups have continued to wage attacks, including sporadic bombings in public areas, and at times targeting businesses in return for “protection money” from the owners, the military previously said.

The BIFF, which the military operation targeted Friday, consists of militants who defected from the Moro Islamic Liberation Front following the peace talks with the government. It further split into a few factions, from which some aligned themselves with the Islamic State group.