MANILA (Reuters) - Philippine security forces killed 54 Islamist militants linked to the Jemaah Islamiah group in a week-long air and ground offensive in the country’s south, an army spokesman said on Monday.The fighting took place near the stronghold of the Moro Islamic Liberation Front, which signed a peace deal with the government in 2014 to end 45 years of conflict that killed 120,000 people and stunted growth in the resource-rich areas.

Major Filemon Tan said two soldiers were killed and nine wounded after air force planes dropped bombs on the militants’ positions and ground troops pounded them with artillery fire, in the town of Butig in Lanao del Sur, from Tuesday.

“The artillery fire did more damage than the bombs,” Tan added. “Our troops saw the enemies fall and, based on estimates, we killed 54. They beheaded two sawmill workers and toppled a power line in the area.”

The fighting has displaced about 2,000 people from five villages in Butig, regional officials said.

About a decade ago, the MILF had expelled Jemaah Islamiah members from the area in preparation for peace talks brokered by Malaysia, and avoid getting a “terrorist” tag from the U.S. State Department.

The military said Jemaah Islamiah-linked militants returned to the area when a law to grant autonomy to Muslim areas, under the government deal with the MILF, failed to pass in Congress.

President-elect Rodrigo Duterte has promised to pursue peace with Muslim rebels, proposing a new federal scheme to grant more political and economic powers to Muslim-dominated areas in the south.