A boy in central Vietnam was killed and two others severely injured as they smashed a rusted iron ball for scrap metal without knowing it was a cluster bomb until it exploded.

News website Vnexpress said in a Sunday report that the three boys Nguyen Van Phong, 11, Nguyen van Phuong, 6 and Tran Ngoc Quyet, 9, discovered the bomb while climbing a hill in Quang Binh Province to dig bamboo roots for food.

The boys were from poor families and they thought of taking metal from the bomb to sell to scrap collectors.

Phong died with burns all over this body while two others are being treated at the hospital, injured by sharpnel.

Thousands of residents including many children, have been killed or maimed by unexploded ordnances dropped by the US Army during the Vietnam War.