Manila, Feb 23 (IANS): At least 20 members of the Bangsamoro Islamic Freedom Fighters (BIFF) group were killed in a clash with Philippine government forces in Pikit, North Cotabato, the military said Monday.

Col. Noel Clement, commander of the army's 602nd Brigade, said the figure was based on information provided by military personnel on the ground and Moro Islamic Liberation Front (MILF) which helped in the operation Saturday.

"We do not have the exact figures because many of the casualties were buried in mass graves by their comrades while they were withdrawing. Based on the reports that we are getting, probably the minimum is 20 casualties," Xinhua news agency quoted Clement as saying.

The army was examining possible locations of mass graves but ruled out exhuming the bodies because "we have to consider the sensitivities of their religion", according to Clement.

Muslim tradition dictates that bodies be buried within 24 hours of death.

The military fired at least 50 artillery rounds towards the BIFF positions in Pikit Saturday based on information provided by the MILF.

The BIFF, founded by former MILF commander Ameril Umbra Kato, defected from the MILF in late 2010 after the latter decided to drop its call for an independent Islamic state.