HANOI - Two children were killed and six others seriously injured after a grenade left over from the Vietnam War exploded while they were playing with it, police said Wednesday.

The children, all 11-year-old classmates, were walking home from school in southern Dak Nong province on Tuesday when they discovered the shell, believed to be from a US-made M79 grenade launcher, a police officer told AFP.

The area was also heavily mined during the conflict, which ended with Vietnam’s reunification in 1975, and unexploded ordnance is regularly discovered in the area, the policeman added, requesting anonymity.

“Two children died on the way to hospital while six others are receiving treatment for serious injuries,” he said.

According to official figures, at least 42,100 people have been killed and 62,100 injured in Vietnam by war-era bombs and mines since the conflict with America ended.