A 12-year-old boy was killed inCambodia when heplayed with an old mortar shell while looking after his family's cows, dpa cited local media as reporting Monday.Two other boys were injured after he found the wartime ordnance inthe western province of Pailin, the Cambodia Daily reported.In a separate incident, a farmer in the north-western province ofBattambang was killed by an anti-tank mine while walking through afield."The incident happened in a banned place because it is full of minesleft over from the civil war." local police chief San Phal said. "Itis a place villagers are not allowed to enter.