The incident happened at a scrap facility in a residential area where many warheads have been found.
An explosion took place early Wednesday in Bac Ninh Province, killing two children, aged one and five, and leaving six others injured, said local officials.
The incident, which destroyed seven houses and unroofed another 10, took place at a scrap facility in a residential area in Yen Phong District, some 40 kilometers (24 miles) northeast of Hanoi.
All what’s left of the facility is now a three-meter deep pit.
The explosion was caused by explosives of unknown origin stored at the facility, said the provincial chair Nguyen Tu Quynh based on preliminary investigation.
Police and soldiers are at the scene rescuing people still stuck under the rubble as well as clearing the site.
Nguyen Van Tuan and his family, who live 30 meters from the scrap facility, were woken up at around 4:30 a.m. to deafening sounds of the explosion as the ground shook, houses collapsed and warheads rained down.
“I run away with my wife and children, stepping over warheads. Only around 1 kilometer away from the scene, there were no more warheads, Tuan said.”
Authorities estimate that the explosion could be felt as far as 5 kilometers from the scene.