Cotabato City, Philippines  - A farmer was killed Thursday in the southern Philippines when a hand grenade in his trouser pocket accidentally exploded, police said.

Twenty people were injured in the accident in Carmen town in North Cotabato province, 960 kilometres south of Manila, police Inspector Winston Seniel said.

Seniel said the victims were preparing food for a wedding to be held later in the day when the explosion occurred.

"The explosion ripped the victim's body," he said. "Some of the body parts were blown up to 10 metres away from the explosion site."

Investigators were still determining where the victim, identified as Karkay Minanga, 26, got the hand grenade.

Police said hundreds of thousands of loose firearms, explosives and other war materials abound in the strife-torn southern region of Mindanao, which is wracked by Muslim and communist insurgencies. (dpa)