The man believed to be the first confirmed Covid-19 patient in North Korea did not have the virus, South Korea said.
The man apparently defected from north to south three years ago, before deciding to return last week.
South Korea said the man reached north by crawling through a drainage pipe on a southern island and then swimming for about a mile.
This weekend, North Korea reported its first suspected case of Covid-19.
He said the patient was a North Korean who had “re-deserted” from the South.
How did the man get to North Korea?
The South Korean military said on Monday the 24-year-old had reached north from Ganghwa Island, near the border.
He apparently crawled under barbed wire in a drain that leads to the Yellow Sea, before swimming north.
“We spotted the exact spot where he fled, because a bag that probably belonged to the man was found,” Colonel Kim Jun-rak said, according to the Yonhap news agency.
- North Korea on alert on “first suspected virus case”
Earlier, North Korean state media said the man defected to South Korea three years ago, before returning earlier this month.
He reached the North Korean city of Kaesong, which is near the coast, on July 19 and was “suspected” of having “the vicious virus.”
North Korean leader Kim Jong-un has reportedly ordered a “maximum emergency system” to contain the virus.
What did South Korea say about human health?
“The person is neither registered as a Covid-19 patient, nor classified as someone who has been in contact with patients infected with the virus,” said Yoon Tae-ho, a senior health official, according to Yonhap .
Viral tests were performed on two people in close contact with the defector, and both tested negative.
South Korea was one of the first countries outside of China to have had a Covid-19 outbreak, but the virus is now largely under control.
With a population of over 50 million, the country records on average just over 50 new cases per day, many of which are imported and then quarantined.
North Korea has not confirmed a single case of Covid-19 – what analysts have long said is unlikely.
What is the frequency of “re-defection”?
It is rare that someone leaves the North for the South and then comes back.
South Korea’s Unification Ministry told the BBC there have been 11 confirmed cases since 2015, the last of which was in 2017.
If confirmed, the man who swam from Ganghwa would be the 12th.
By Subin Kim, BBC News, Seoul
Although he said the re-defector was only ‘suspected’ of having Covid-19, Pyongyang appears to want to stress that the outside world – especially the South – must be blamed for the possible violation of its anti-epidemic measures. .
So far, it seems unlikely that the man who returned to Kaesong after three years in South Korea really has Covid-19.
South Korean authorities have denied it, and Pyongyang has an apparent lack of testing capacity anyway.
Experts agree that Pyongyang is trying to dissuade its people from blaming the regime for the hardships the pandemic has caused in their lives.
Whether the cases are confirmed or not, it is evident that the North Korean economy is faltering from its vigorous prevention measures – including the closure of its border trade route with China.
Pyongyang could try to use this incident as an excuse to ask Seoul for help – like medical supplies or food.