COTABATO CITY, Philippines -- An extortion gang being linked to the Abu Sayyaf extremist group claimed responsibility for Thursday afternoon's bomb attack in Midsayap, North Cotbatao that wounded five persons, including two children.

Midsayap Mayor Manuel Rabara said he received a call before the blast from a man who introduced himself as being from the al-Her Hajj.

The same man, he said, called up again after the explosion that ripped through a passenger van.

North Cotabato Governor Jesus Sacdalan said the al-Her Hajj gang is actually the al-Khobar extortion group, which has been blamed for the series of explosions that hit Central Mindanao last year.

Military and police officials in the region had earlier reported that at least two persons died in the attack.