PHNOM PENH, May 6 (FN) — Two boys were killed and another one was seriously wounded when a war-era bomb exploded in a field in northwestern Cambodia's Oddar Meanchey province on Friday, provincial police chief Major General Men Ly said.

The three boys, aged between 12 and 15 years old, found the bomb when they tended cows in a rice paddy field near their village, he said.

"They had tried to break apart the bomb, causing the ordnance to explode," he told Fresh News, adding that police had not yet determined the type of the bomb.

"Two boys died instantly from the blast, as the third was in critical condition," he said.

Landmines and unexploded ordnance killed 18 Cambodian people and injured 93 others in 2015, according to a government's report.

The Southeast Asian country is one of the world's worst countries suffered from landmines and unexploded ordnance. An estimated 4 to 6 million landmines and other munitions were left over from three decades of war and internal conflicts that ended in 1998.

The country is seeking about 36 million U.S. dollars a year for the next decade to entirely get rid of all types of mines and explosive remnants of war.