The Maute group forced the civilians off their truck at a roadside checkpoint in Marawi City on Wednesday and murdered them after they were identified as Christian, local media reported.
Harrowing images show the group lying dead face-down in the grass, amid reports that villagers are afraid to move the bodies because terrorists are still in the area.
According to Daily Mail, one policeman was similarly caught at a checkpoint set up by the militants and beheaded on Wednesday, President Rodrigo Duterte said.
It comes as 100 US-trained special forces aboard helicopters and armoured tanks battled to retake the besieged southern city from rampaging jihadis.
