At least 10 people were killed and dozens wounded — including soldiers and police — in a twin bombing Monday involving a suicide attacker on a southern Philippine island that is a stronghold of Islamist militants, officials said.

The attack happened in Jolo in Muslim-majority Sulu, where government-backed security forces have long been fighting the Abu Sayyaf group.

Five soldiers and four civilians were killed in the first blast, when an improvised explosive device attached to a motorcycle parked outside a supermarket blew up, Lieutenant General Corleto Vinluan told reporters.