Three people were killed and 33 wounded in a grenade explosion on Saturday during a cockfight in the southern Philippines, police said. The victims were watching a cockfight in the village of Lawili in North Cotabato province, 930 kilometres south of Manila, when the blast occurred, dpa reported. Senior Superintendent Cornelio Salinas, the provincial police director, said a personal rivalry was believed to have been the motive behind the attack. "Apparently two rival groups encountered each other at the cockfight and then someone lobbed the grenade," Salinas said.