Six Cambodian farmers were killed when their truck hit an old anti-tank mine planted by Khmer Rouge guerrillas during the country's civil war, police say.
The men were driving through a flooded field in northern Preah Vihear province on Wednesday evening when the explosion occurred, provincial police chief Sy Kiri said.
A seventh man was seriously injured.
"The anti-tank mine was left over from the civil war and it was planted by the Khmer Rouge soldiers to defend their area from the government forces," Sy Kiri said, adding the area was a major battle field in the 1980s and has not yet been demined.
The farmers had been driving through the flooded area on the way to inspect their paddy fields, which have been left inundated by recent heavy rains.
Nearly three decades of civil war gripped Cambodia from the 1960s onwards, leaving the poverty-stricken country as one of the world's most heavily mined places.
The brutal hardline communist Khmer Rouge regime was responsible for the deaths of up to two million people from starvation, disease, overwork or execution during the "Killing Fields" era in the late 1970s.
After they were ousted from power by the Vietnamese in 1979, they continued to wage a savage guerrilla war until the 1990s, with remote parts of Preah Vihear acting as their last holdout.
In 2012 leftover landmines and other unexploded ordnance killed 43 people and caused 142 injuries, according to official statistics.
Late last month, two Cambodian children and a man were killed when their buffalo cart hit an anti-tank mine left over from the country's civil war in northwestern Oddar Meanchey province.
