Philippine military officials say more than 100 troops attacked a mountainous stronghold of two al-Qaida-linked Abu Sayyaf fighters, including one on the FBI's list of most-wanted terrorists, sparking clashes that killed at least seven militants in the country's south.

Army brigade commander Col. Carlito Galvez says the offensive early Monday targeted Abu Sayyaf commanders Isnilon Hapilon and Puruji Indama in the mountainous outskirts of Tipo Tipo town on Basilan Island. He says it was not immediately clear if either was hit during the main assault and two nearby clashes that followed.

Washington has offered a $5 million reward for the capture or killing of Hapilon. He has been accused of involvement in deadly bombings, kidnappings and beheadings, including of Americans.