Police in the central province of Quang Tri have seized a 300-kilogram (660 lb) Vietnam War-era bomb while it was being transported for sale.
A 39-year-old Vietnamese man was stopped by police for a check while driving a motorbike pulling a cart with an unexploded M117, an air-dropped general-purpose bomb used by the United States during the war, at around 9 p.m on Monday.
The man said he and five other people found the bomb underground in a forest, using a metal detector.
The bomb, which contains 185 kilograms of explosive, was handed over to the provincial military forces for safe disposal.
Quang Tri Province, home to the Vietnamese demilitarized zone which once divided the country into two, was hit hard by air raids during the war.
Officials estimate 400,000 unexploded bombs and munitions remain buried across 480,000 hectares (1.2 million acres) of the province, including residential areas.
Unexploded ordnance still covers a fifth of Vietnam and explosions occur frequently, killing more than 1,500 people every year and maiming 2,200 more, according to official data.
Last month, police launched an investigation against five people in southern Vietnam for dismantling a wartime bomb to take the explosive for sale.