The Philippine military chief says troops have launched airstrikes and ground assaults against one of Southeast Asia's most-wanted terror suspects who is trying to establish a new base for an alliance of armed groups backing the Islamic State group.

Gen. Eduardo Ano says airstrikes targeted the group of elusive militant leader Isnilon Hapilon on Wednesday and Thursday. Hundreds of troops began pursuing him and allied militants in the mountainous hinterlands of Butig town in southern Lanao del Sur province.

Ano said Friday that Hapilon, who is on the U.S. Department of Justice list of most-wanted terrorists, moved to Butig from his stronghold on southern Basilan island a month ago to look for a base for his new alliance of small extremist groups.