The United States gave the Philippine air force on Tuesday its first surveillance drone system, as the two nations step up co-operation in the battle against militants.

Washington has been boosting its backing for Philippine counter-terror efforts since Daesh supporters seized parts of the southern city of Marawi last year, sparking a deadly five-month battle.

The unmanned aerial vehicle system worth $13.2 million, including six drones, turned over to Philippine troops was the latest US military assistance.

“Assets like the ScanEagle will significantly improve the (Philippine military’s) ability to detect terrorist activities, piracy activities, territory encroachment,” US Ambassador to Manila Sung Kim told reporters, referring to the drones.

Philippine Defence Secretary Delfin Lorenzana said the system, equipped with cameras and aircraft that can fly for 24 hours, would support operations against militants in the south.

Meanwhile, it is reported that two members of the Daesh-linked Abu Sayyaf terror group involved in the abduction of two US missionaries and 18 other people from a resort on the island province of Palawan in 2001 were arrested in Zamboanga City in Mindanao.

Dante Guerran, the chief of the National Bureau of Investigation (NBI), presented to media the suspects identified as Hood Abdullah and Jimmy Bla who were arrested in separate operations by government forces in Zamboanga City in late February.

Guerran said the two suspects were positively identified by the hostages as among the terrorists who stormed a resort in Palawan on May 27, 2001 and abducted its 20 guests including American missionaries Martin Burham and his wife Gracia.

Abdulla was a “sleeper” agents working as a security guard in a motel in Zamboanga City, who was responsible for spotting potential kidnap victims, Guerran said.

On the other hand, Guerran said Bla was an explosive bomb expert who provided the terrorists with material and logistical support.

Police and military intelligence records showed the terrorists brought all their hostages to various areas in Mindanao including the island province of Sulu while hey negotiated with the families in their demand for ransom in exchange for their release.