Two boys were killed when a Khmer Rouge-era B40 rocket exploded in a forest in Kampong Thom province on Friday afternoon.

Chok Nak, 12, and Ouy Chhan, 14, along with a third boy, found the rocket while planting animal traps in a forest near their house, said Popoak commune police chief Pen Samath, citing the third boy.

The rocket exploded after the two boys struck it with a small axe, Samath said. The third boy ran to alert his parents after hearing the explosion and witnessing smoke rise from the trees.

“We do educate people about encountering UXOs, but for some poor, uneducated children, they try to take UXOs and sell them,” said Samath.

While there have been major gains in demining Cambodia in recent years, unexploded ordinances still plague the country, especially in the north.

There were 28,306 recorded casualties of UXOs in the country from 1992 to 2015, according to the United Nations Development Programme.

Last month, the UNDP launched a $11 million demining initiative in Cambodia.