HANOI, Vietnam (AP) -- A police officer says four fishermen were killed when a Vietnam War-era bomb they were handling exploded.

Tran Van Duong says the men were killed instantly while trying to remove explosive materials from the bomb in southern province of Tay Ninh.

Duong said Wednesday the men were two sets of brothers, all in their 20s.

The explosion occurred in Don Thuan village, a communist stronghold that was target of U.S. bombardment and firing during the war.

Government figures say unexploded ordnance left over from the war has killed more than 42,000 people and wounded some 62,000 since the conflict ended in 1975.