North Korean soldiers shot dead a suspected South Korean defector after interrogating him at sea, and burned his body over coronavirus fears, Seoul military officials said Thursday.
The man had disappeared off a patrol vessel near the western border island of Yeonpyeong, the South Korean defence ministry said in a statement.
He was wearing a lifejacket, a military official told AFP, adding that "circumstances tell us that there was an intent to defect", without providing evidence.
According to the South's Yonhap news agency, the man was located by North Korean forces and questioned from a boat by an official wearing protective equipment.
The killing took place after an "order from superior authority", Yonhap cited South Korean officials as saying.
Seoul's defence ministry condemned the shooting as an "outrageous act".
"We sternly warn North Korea that all responsibilities for this incident lie with it," it said.
In July, a North Korean defector who had fled to the South three years ago sneaked back over the heavily fortified border into the impoverished nation. His crossing prompted North Korean officials to put the border city of Kaesong under lockdown amid fears that he may have carried the coronavirus.
U.S. Forces Korea commander Robert Abrams said earlier this month that North Korean authorities had issued shoot-to-kill orders to prevent the coronavirus entering the country from China, creating a "buffer zone" at the border.
The isolated North — whose crumbling health system would struggle to cope with a major virus outbreak — has not confirmed a single case of the disease that has swept the world since first emerging in China, the North's key ally.
Pyongyang closed its border with China in January to try to prevent contamination, and in July state media said it had raised its state of emergency to the maximum level.