At least 21 suspected members of the extremist Abu Sayyaf Group have been killed in intensified military operations launched recently following the beheading of a teenager in Sulu province, military said on Sunday.

Armed Force of the Philippines spokesman Brig. Gen. Restituto Padilla said the operations against the bandits have not stopped.

"They will continue on in compliance to the instructions of the commander-in-chief," he said in a text message.

President Rodrigo Duterte has renewed his order to the military to destroy the Abu Sayyaf after Patrick Almodavar, 18, was beheaded this week.

"To date 21 members of the KFRG (kidnap for ransom group) ASG have been confirmed killed during battles the past few days," Padilla said.

Among those killed were ASG subleader Mohammad Said, alias Ama Maas, and his son, and two other subleaders.

Padilla said 17 soldiers were wounded. But he said most of whom only suffered superficial wounds.

According to a resident in Sulu who refused to be named, heavy bombardment from the military were heard even during night time.

Some of the recovered bodies were brought to the police station using truck, the source said. DMS