At least 29 people were killed when a Philippines Air Force plane carrying troops crashed on landing in the south of the country and broke up in flames on Sunday.
So far at least 50 people on board were brought to a hospital and troops were trying to search for the rest, military officials said.
The aircraft had 92 people on board, including three pilots and five crew and the rest were army personnel, military officials said. The pilots survived but were seriously injured and at least four villagers on the ground were injured, officials said.
The military plane crashed on landing shortly before noon in the Bangkal village in the mountainous town of Patikul.
The plane was transporting troops from southern Cagayan de Oro city, military chief Gen Sobejana said.
“It’s very unfortunate,” Gen Sobejana told reporters. “The plane missed the runway and it was trying to regain power but failed and crashed.”
A military spokesman, Col Edgard Arevalo, said there was no indication of any attack on the plane, but that a crash investigation had not begun and efforts were focused on rescue and treatment.
Government forces have been battling Abu Sayyaf militants in the predominantly Muslim province of Sulu for decades.
Gen Sobejana said in a message to Reuters that the plane had crashed a few kilometres from Jolo airport at 11.30am and had been carrying troops.
It was not immediately clear what caused the crash, but weather reports indicate that it has been raining in the central Philippines.
“We are currently attending to the survivors who were immediately brought to the 11th Infantry Division station hospital in Busbus, Jolo, Sulu,” he said.
There are hopes that 17 men on the plane still unaccounted for could still be alive.
Some of the soldiers were seen jumping out of the plane before it hit the ground and exploded into flames, said Major General William Gonzales, commander of the Joint Task Force-Sulu.
"This is a sad day but we have to remain hopeful," Gen Gonzales said in a statement. "We enjoin the nation to pray for those who are injured and those who have perished in this tragedy."
The US and the Philippines have separately blacklisted the Abu Sayyaf as a terrorist organisation for bombings, ransom kidnappings and beheadings. It has been considerably weakened by years of government offensives but remains a threat.