Government forces clashed with members of the rebel group Maute in Marawi City, Lanao del Sur.
Reports said armed men have taken over the Amai Pakpak Medical Center, with the group replacing the Philippine flag with a black flag, supposedly representing the Islamic State (ISIS).
Fr. Chito Soganub, along with other churchworkers, were taken from the St. Mary’s Cathedral.
Armed Forces of the Philippines (AFP) First Infantry Division Spokesman Lt. Col. Jo-Ar Herrera said Abu Sayyaf leader Isnilon Hapilon was among the armed men seen in the area.
President Rodrigo Duterte, who was in Moscow to meet Russian President Vladimir Putin, declared martial law in Mindanao, citing the attack as possibly rebellion.