Four children and a 20-year-old man were killed in an accidental explosion of a rifle grenade in a northern Philippine province, dpa quoted police sources as saying Sunday. One of the children found the M203 rifle grenade in a river near their homes in Santa Clara village in Quezon town, Nueva Ecija province, 120 kilometres north of Manila, on Saturday. Provincial police chief Senior Superintendent Napoleon Taas said the children, aged between five and seven, were playing with the rifle grenade when it accidentally exploded. The adult fatality was near the children when the explosion occurred, he added. Taas said shrapnel recovered from the blast site has been sent to the national police crime laboratory for further analysis to help determine where the rifle grenade came from.