South Korea on Thursday saw the highest number of novel coronavirus cases being confirmed in one day, adding to growing fears about an epidemic here.

On Thursday, the government coronavirus response team revealed that four individuals -- tagged the 20th to 23rd patients -- have been confirmed, pushing up the total to 23.

Meanwhile, another patient has made a full recovery and was set to be released later in the day. The patient set for release Thursday is a 35-year old Chinese national, who was the first confirmed case in Korea. The patient’s release comes a day after the second confirmed patient -- a 55-year old Korean man -- was discharged after making a full recovery.

Of Thursday’s cases, three are Korean nationals who had contact with patients confirmed earlier, and one is a Chinese national who entered Korea as a tourist.

The 20th patient is a member of the 15th patient’s family and had been in self-quarantine for five days when she was diagnosed. The 15th patient arrived in Korea on Jan. 20 and was diagnosed Sunday. Both the 15th and 20th patients are in isolation at the Armed Forces Capital Hospital.

The 21st patient was also diagnosed during self-quarantine, according to authorities. The 59-year-old woman had come into contact with the sixth patient -- a 55-year-old man believed to have contracted the virus in Korea from the third patient. The sixth patient has now been linked to three subsequent cases.

The 22nd patient is a 46-year old man, a family member of the 16th patient, whose daughter was confirmed to have the virus Wednesday.

The last of Thursday’s confirmed cases is a 58-year Chinese woman who entered the country on Jan. 23 as a tourist.

With the number of cases in Korea and China rising, there have been public calls to impose entry restrictions for a wider area of China.

From midnight Monday, Seoul restricted entry to foreigners with a record of visiting China’s Hubei province within 14 days of arriving in Korea. Seoul also introduced a more stringent immigration process for people arriving from China. However, the measures have been criticized for lacking efficacy as coronavirus cases have been confirmed across China.

Seoul, however, appears reluctant to move ahead of international society on the issue.

“The safety of the people is the top priority, but World Health Organization guidelines, and the efficacy and international society’s trends (on expanding entry restrictions) must be taken into account,” Seoul’s Minister of Foreign Affair Kang Kyung-wha said Thursday.

She also said that factors such as Koreans contracting the virus in third countries and more cases being confirmed in other countries must be taken into account when considering barring entry to travelers coming from all areas of China.

Of Korea’s 23 confirmed patients, two are believed to have contracted the virus in Singapore, one in Japan and another in Thailand.

Kang also revealed that Koreans aboard a Japanese cruise ship do not currently show symptoms of coronavirus infection and that the Korean diplomatic mission in Japan was closely monitoring the situation.

By Choi He-suk (cheesuk@heraldcorp.com)