Police shot and killed two suspected members of a local cell of the Islamic State (IS) group in the southern Philippines late on Sunday, authorities on Monday said.

Senior Superintendent Ferlu Silvio, the provincial police chief for Davao del Sur police, identified the slain suspects as Norhan Delangalen Sinapan and his brother Norton Delangalen Sinapan.

Norhan, Silvio said, was the leader of a cell of the Islamic State called Dawlah Islamiyah in the city of Digos in Davao del Sur province.

Silvio said the operation against the brothers were carried by combined police units, who swooped down on their hideout at a seaside community at 11 p.m. local time.

Recovered from the slain suspects were a handgun, several rounds of ammunition, a component for an improvised bomb, a fragmentation grenade and two black flags with IS markings, the police official said.

The southern Philippines has been on alert following reports terrorists who swore allegiance to the terror network had regrouped after they were routed and expelled by Philippine troops from Marawi City late last year after five months of heavy fighting.

A series of bombings in the southern Philippine town of Isulan last August and September that killed four people and wounded scores of others were blamed on local IS-affiliated extremists.