The Korea Centers for Disease Control and Prevention says it is currently testing 15 suspected coronavirus cases.
The agency said it is investigating people who have been in contact with the 55-year-old South Korean man who was confirmed as the country's fourth case on Monday.
They are also trying to track his movements since he returned from the Chinese city of Wuhan early last week.
The man is currently being treated in an isolation ward at a state-designated hospital.
Apart from the four confirmed cases so far, there have been no additional reports of infection.
Ninety-seven people who were earlier held in quarantine for showing pneumonia-like symptoms have been released after testing negative for the disease.■
<Photo: Yonhap News>
