The incident occurred at the overland bus terminal in southern Digos City, the Philippines News Agency reported, quoting the military.

The report said details of the incident were sketchy and there were conflicting estimates of the casualties. A Xinhua report, quoting the military, said at least three people were killed in a bus as it was entering the terminal.

One military spokesman was quoted as saying there were two explosions in two buses.

Islamic militant groups have been fighting in the Mindanao for separate Muslim homeland and some local groups also are believed to be allied with the Southeast Asia terrorist group Jemaah Islamiya.