President Moon Jae-in on Monday ordered an all-out check on every individual who has recently traveled here from Wuhan, China, as Korea confirmed its fourth case of the Wuhan coronavirus amid growing public fears over the viral illness that has already caused 80 confirmed deaths in China.

The government raised the level of the four-tier infectious disease alert to the second most severe rung, after a 55-year-old Korean man, who had visited Wuhan, Hubei province, tested positive for the coronavirus earlier in the day.

The man, who showed no symptoms of infection when he was screened at an airport upon his return to Korea on Jan. 20, received treatment at a medical facility on Jan. 21 for cold symptoms. On Saturday, he developed symptoms of a high fever and aching muscles, and was put under close observation. He was diagnosed with pneumonia Sunday, according to the Korea Centers for Disease Control and Prevention.

Adding fuel to public health concerns, the man was confirmed to have carried out normal activities after he contracted the virus, according to the agency. An in-depth inspection following his activities is underway.

The latest case comes a day after a 54-year-old Korean resident of Wuhan, who returned to Korea on Jan. 20, tested positive, in the third confirmed case of the coronavirus here.

The man also showed no symptoms during screening for the virus at the airport and had led normal activities without being identified or monitored by health authorities.

According to his movements disclosed by the KCDC on Monday, he received treatment at a plastic surgery clinic, dined at restaurants, took a stroll along the Han River and stayed in a hotel in southern Seoul before visiting his mother in Ilsan, Gyeonggi Province.

Seventy-four people came into contact with the man, according to the public health agency. One of them had symptoms of infection and was placed in isolation, but tested negative. The others are under self-imposed isolation and being closely observed by health authorities.

The medical facilities and hotel he visited have all been disinfected, the KCDC said.

Two other cases -- a 35-year-old Chinese woman and a Korean man -- were confirmed on Jan. 20 and Friday, respectively.

Fifty-seven people had shown symptoms of the virus as of Monday afternoon. One person was awaiting test results, and the remaining 56 people have tested negative for the virus.

The Korean government has stepped up efforts to contain the spread of the virus by tightening checks on passengers entering Korea and expanding the range of people to be put under quarantine and on monitoring lists among those who visited China.

In a meeting with senior secretaries, President Moon Jae-in ordered all-out, preemptive measures -- such as transparent disclosure of information to the public as well as mobilization of medical personnel from the military -- to rein in the spread of the corona virus, according to Yoon Do-han, senior secretary for public communication.

He also urged close monitoring of the coronavirus’ impact on the economy. The finance minister is set to hold an emergency meeting Tuesday, according to Yoon.

The Foreign Ministry raised the travel advisory level for Wuhan and the Hubei province region to “red alert,” also second-highest in the country’s four-tier travel warning system.

The government is reportedly conducting a final review to send a chartered plane to Wuhan to evacuate an estimated 600 Koreans believed to be staying in and around Wuhan.

All of China is now classified as a “coronavirus risk area,” with travelers coming from the country required to fill out health forms upon arrival. If a person from Wuhan or nearby areas shows any signs of a fever or breathing problems, he or she will be placed under quarantine starting from Tuesday. Those who have visited other parts of China and who show symptoms of pneumonia will be put in isolation.

Public fears are mounting in Korea, with the presidential website flooded with petitions demanding a ban on the entry of all Chinese travelers. More than 480,000 people signed the petitions as of Monday afternoon.

There were 2,744 confirmed cases across China, 461 of whom are in critical condition, as of Sunday midnight, China’s National Health Commission announced, with a combined population of over 57 million people placed under full or partial lockdown.

The end of the Lunar New Year holiday in China was pushed back to Sunday from Thursday, and the reopening of schools was postponed until further notice to “reduce mass gatherings” as part of efforts to block the spread of the coronavirus.

The youngest patient is a 9-month-old girl in Beijing.

The virus is rapidly spreading outside mainland China, with Hong Kong, Macao, Thailand, Japan, Taiwan, Vietnam, Singapore, Malaysia, Nepal, France, Australia, the US and Canada having reported confirmed cases of the coronavirus.

The KCDC advised citizens to look after their personal hygiene -- such as washing hands and wearing masks. Those showing pneumonia-like symptoms should immediately contact an emergency call center by dialing 1339, it said.