Hieu Nghia village official Le Van Giang said three children aged 4 to 11 died at the scene Sunday afternoon and a 6-year-old boy died at the hospital. The blast seriously injured two other children and three men.
Giang said the shell exploded when the children who found the shell from bamboo brush were playing with it. A villager found the shell five years ago when dredging a canal.
The village in Vinh Long province was a communist stronghold during the war.
Vietnamese government figures show unexploded ordnance have killed more than 42,000 people since the war ended in 1975.
MOST READ
LATEST STORIES