The Philippine air force is on the verge of receiving two Cessna 208B Caravans equipped for intelligence, surveillance, and reconnaisance (ISR) missions.

The revelation of the delivery timeframe came during a television interview by US ambassador to the Philippines, Sun Kim.

"We're deeply concerned about security situation in Marawi," says Kim. "We'll be providing two aircraft for intelligence, surveillance, and reconaissance activies in the coming weeks. These are Cessna 208s fitted with very useful ISR equipment."

Manila has been battling an Islamic insurgency on the southern island of Mindanao. Hostilities escalated in recent weeks with a battle in and around the town of Marawi.

The two aircraft appear to stem from a May 2016 contract awarded by the US Department of Defence to L-3 Communications.

The $14 million contract involved modifying Cessna 208Bs for the ISR mission. The aircraft were earmarked for four countries with insurgencies: Chad, Cameroon, Niger, and the Philippines.

Combat in and around Marawi has seen the Philippine air force's obsolescent Rockwell OV-10B Bronco aircraft and Korea Aerospace Industries (KAI) FA-50 fighters conduct raids against enemy forces.

Media reports from the Philippines indicate that the FA-50s were temporarily pulled from combat operations after a "friendly-fire" incident, in which a bomb dropped by an FA-50 killed two soldiers and injured 11.

Nonethless, Filipino officers have otherwise been satisified with FA-50's performance in combat.