MANILA, Philippines (AP) — A Philippine air force C-130 aircraft carrying troops crashed in a southern province Sunday after missing the runway and at least 40 people on board were rescued from the burning wreckage, the military chief said.

Chief of Staff Gen. Cirilito Sobejana did not immediately say how many people were on board the aircraft and if there were casualties after it crashed on landing shortly before noon in Bangkal village in the mountainous town of Patikul in Sulu province.

The plane was transporting troops from southern Cagayan de Oro city, Sobejana said. Government forces have been battling Abu Sayyaf militants in the predominantly Muslim province of Sulu for decades.

“It’s very unfortunate,” Sobejana told reporters. “The plane missed the runway and it was trying to regain power but failed and crashed.”

Sobejana said at least 40 people on board were brought to a hospital and troops were trying to save the rest.

It was not immediately clear what caused the crash.

It has been raining in the central Philippines but it was not immediately clear if the weather in the Sulu region has been affected. The airport in Sulu’s main town of Jolo is located a few kilometers (miles) from a mountainous area where troops have battled the Abu Sayyaf. Some militants have aligned themselves with the Islamic State group.

The United States and the Philippines have separately blacklisted the Abu Sayyaf as a terrorist organization for bombings, ransom kidnappings and beheadings. It has been considerably weakened by years of government offensives but remains a threat.