Manila: Pro-Islamic State militants stormed a school in the southern Philippines early on Wednesday and are holding several students hostage, police said, on the same island where fighting between government troops and Islamists has entered its fifth week.

A police report said about 300 armed men, among them members of the Bangsamoro Islamic Freedom Fighters (BIFF), stormed a school in Pigcawayan town in North Cotabato province on Mindanao island and were holding some students captive.

Members of the BIFF were engaged in a gun battle with the military, the police chief at Pigcawayan, Chief Inspector Realan Mamon, said in a radio interview.

"We can confirm that they occupied a school and there were civilians trapped. We are in the process of determining how many were trapped and their identities," Mamon said.