About 50 heavily armed members of the Maute group, which supports the Islamic State group, raided the local jail in the southern city of Marawi on Mindanao island on August 27 and freed eight comrades who were arrested barely a week ago, police said.
Fifteen other detainees also escaped in the raid, said a provincial jail warden.
Authorities said they were investigating the jailbreak and the reason why security had not been increased after high-risk suspects were brought in.
It was the latest of several mass escapes from Philippine jails. In 2009, more than 100 armed men raided a jail in the southern island of Basilan, freeing 31 prisoners including several Muslim guerrillas.
The Maute group is one of several Muslim gangs in Mindanao, the ancestral homeland of the Muslim minority in the Philippines. It has carried out kidnappings and bombings and is believed to have led an attack on an army outpost in the Mindanao town of Butig in February.-
