A North Korean defector suspected of having fled back to his communist homeland is unlikely to have been infected with the new coronavirus here despite Pyongyang's claim that he had virus symptoms, Seoul's health authorities said Thursday.

North Korea's state media claimed Sunday that a defector returned home from South Korea with suspected virus symptoms, prompting the country to adopt a "maximum emergency system" against the coronavirus.

The Korea Centers for Disease Control and Prevention (KCDC) said they did not find any traces of COVID-19 from 16 samples of items that belonged to the defector.

Health authorities said they also have not yet found evidence that he had come in contact with virus patients in the South. South Korea plans to carry out COVID-19 tests on eight acquaintance of the defector as well.

"As the defector is believed to have fled to the North on July 19, the peak of the incubation period has also already passed," KCDC Deputy Director Kwon Joon-wook said in a briefing. "But we still need to keep a watchful eye on any developments."

The defector, who came to South Korea in 2017, is believed to have swum across the border from the western border island of Gwanghwa after going through a drain under barbed wire fences to evade border guards.

The 24-year-old defector was facing arrest on a court-issued warrant on charges of raping a female acquaintance last month, according to police.

South Korea's new coronavirus cases dipped to the lowest in more than a month on Thursday as imported cases dwindled from last week's record high over infections traced to virus-hit Iraq and Russian sailors.

The country added 18 cases, including 11 imported cases, raising the total caseload to 14,269. (Yonhap)