Moro Islamic Liberation Front rebels stand guard at the entry of Camp Darapanan, Sultan Kudarat in Mindanao. (AFP)

Seven former Muslim rebels have been killed in Maguindanao in an attack claimed by the Islamic State group, military and police authorities reported Saturday.

The dead were all members of the Moro Islamic Liberation Front (MILF), formerly the country’s largest guerrilla group but which began decommissioning weapons last month under the terms of a 2014 peace treaty.

A pro-IS armed group called Dawlah Islamiyah attacked an MILF camp near the town of Shariff Saydona on Friday, sparking fighting lasting several hours, said Lieutenant Colonel Ernesto Gener, commander of the Philippine Army’s 57th Infantry Battalion said.

IS claimed responsibility in a communique seen by SITE Intelligence Group, a Maryland, USA-based company which monitors jihadist activity.

The jihadists said eight MILF members were killed, but local police commander Lieutenant Colonel Arnold Santiago told reporters the authorities were only aware of seven deaths.

Locals said they saw seven bodies being loaded onto a boat at a riverbank in Shariff Saydona.

MILF spokesman Von al Haq declined to comment.

The MILF peace pact ended decades of Muslim rebellion that had claimed 150,000 lives by government estimates in the Mindanao region, home to the Catholic nation’s large Islamic minority.

The MILF was put in charge of a Muslim autonomous region as part of the peace accord, but President Rodrigo Duterte said IS is attempting to set up a Southeast Asian stronghold there.

Hundreds of pro-IS gunmen seized Marawi City in May 2017, sparking a five-month battle that left more than 1,000 people dead.

The MILF, sometimes with the military’s help, has in recent years waged an armed campaign to flush out a number of pro-IS groups operating in the swampy farming region around Shariff Saydona.