Hanoi  - Three Vietnamese children were killed when a shrapnel bomb, believed to be left over from the Vietnam War, exploded in central Vietnam, an official said Thursday.

Tran Duy Quyet, 14, Pham Nhu Hoi, 13, and Dao Ba Thanh, 12, were tending buffaloes on a field in Hai Chanh commune in the central province of Quang Tri Thursday morning when the bomb exploded, Bui Thi Thu Van, an official with the commune's People's Committee said.

All three children were killed on the spot, he said.

"We don't know why the bomb exploded, but we think that the children were playing with the bomb," Van said. "We found them lying dead on the field after the explosion."

The official added that several unexploded shrapnel bombs were also found at the site after the incident.

Quang Tri province, located 620 kilometers south of Hanoi, was the location of one of the fiercest battles during the Vietnam War.

During the war, US warplanes dropped some 15 million tons of bombs on Vietnam. The bulk of the unexploded ordnance remains in the central and southern regions of the country, particularly around the demilitarized zone that divided North and South Vietnam until the end of the war in 1975.

Dozens of Vietnamese are killed every year by bombs, mines and grenades.

Last month, two scrap metal dealers were killed and another seriously injured when a wartime artillery shell exploded in the central highlands of Vietnam. The
105-millimeter shell went off when they were sawing it to remove the explosive. (dpa)