MANILA, Philippines, March 5, (AP): Rescuers found the wreckage of a Philippine fighter jet and the bodies of its two pilots on Wednesday in a mountainous region in the country’s south where they had been deployed on a nighttime mission to fight communist guerrillas, military officials said. The FA-50 jet lost communication during the combat mission with other air force aircraft after midnight Tuesday before reaching a target area in southern Bukidnon province.

The other aircraft were able to return safely to an air base in central Cebu province after carrying out assaults, military officials said. The FA-50 jet was deployed with other air force aircraft to provide combat support to troops battling dozens of suspected New People’s Army guerrillas near Cabanglasan town in Bukidnon, the military said.

"It was a total wreck,” regional military commander Lt Gen Luis Rex Bergante said of the fighter jet’s wreckage, which he said was found by Filipino special forces in a jungle on Mount Kalatungan in Bukidnon. A regional military spokesperson, Lt Col Francisco Garello, said without elaborating that the bodies of the two air force pilots were found near the wreckage.

Pilots can eject from the supersonic jets in case they encounter any problems but the Philippine air force said it remained unclear if the two pilots aboard the FA-50 ejected as it plummeted. It was also not immediately clear what caused the crash of the supersonic jet, which was acquired by the Philippine government from a South Korean company about a decade ago.

An investigation was underway, the air force said. The rest of the country's 11 FA-50s were grounded following the incident, according to the Philippine air force. The Philippines acquired 12 FA-50s multi-purpose fighter jets starting in 2015 from South Korea’s Korea Aerospace Industries Ltd. The 18.9 billion peso ($331 million) contract had been the biggest under a military modernization program that has been repeatedly stalled by a lack of funds.

The Philippines has plans to acquire another 12 fighter jets from South Korea. The military estimates about 1,000 communist guerrillas remain after decades of battle setbacks, surrenders and factional fighting. Peace talks brokered by Norway collapsed under previous President Rodrigo Duterte after both sides accused the other of continuing deadly attacks despite the negotiations.