“The situation is very grave,” President Moon Jae-in said during a visit to Daegu on Tuesday, wearing the uniform of a government emergency official and vowing full government support. “We will achieve a victory in the fight against this virus.”

Most of the country’s infections are linked to the Shincheonji Church of Jesus in Daegu, a group that mainstream churches see as a cult. Shincheonji claims its founder, Lee Man-hee, has donned the mantle of Jesus Christ and will take 144,000 people with him to heaven on the day of judgment.

The church on Tuesday said it had agreed to provide authorities with the names of all its members in South Korea, estimated by media at about 215,000 people. The government plans to conduct coronavirus tests on all of the members “as soon as possible” once it has the information, the prime minister’s office said in a statement.

“We have constantly requested the list based on our assessment that it is essential to test all of the church members in order to contain the spread of the virus and relieve public anxiety,” the statement said.

Vice Health Minister Kim Kang-lip said the priority was to test some 1,300 of the 9,200 members of the Daegu church who are showing symptoms, which he said would be completed by Wednesday.

“We will make utmost efforts with the goal of stabilising the situation in Daegu within four weeks,” he told a briefing, adding that the government would trace all other Daegu citizens having symptoms for isolation and checks.

The church, which has faced public criticism of its handling of the outbreak, asked the government to ensure the personal details in the lists do not become public.

“We have been actively cooperating with the government to prevent the spread of the virus and overcome the outbreak,” Lee Man-hee said in a letter posted online.

Besides its members, the church would also check the people in training programmes to become full members, he added.

“All of these will be implemented on the premise that the government takes steps to protect their personal information,” Lee said.

Leading Korean health official is cult member infected with coronavirus

One of the cabin crew of Korean Air has tested positive for coronavirus, the airline said on Tuesday, prompting it to shut its office near the Incheon International Airport, where the crew briefing room is located.

Details of routes and flights flown by the employee were not immediately available.

The official, whose name has been kept from the public, is the head of the Infection Preventive Medicine Department in Daegu. The official, who was in charge of the district’s fight against the virus, identified himself as belonging to the church after he tested positive for the virus, said Daegu City Mayor Kwon Young-jin.

Consequently, 50 other health officials who worked with him have been quarantined at their homes as a precautionary measure.

The escalation in the alert level allows the government to send extra resources to Daegu city and Cheongdo county, which were designated “special care zones” on Friday.

“The coronavirus virus is more contagious and spreads quickly during the early stage of the outbreak, and therefore pre-emptive measures are needed considering a possibility that the virus could develop to a nationwide spread from a community spread,” Health Minister Park Neung-hoo told a news conference. “We believe a week to 10 days will be crucial to determine the spread of the coronavirus.”

Education Minister Yoo Eun-hae told the news conference that kindergartens, elementary and secondary schools will start the new semester one week later on March 9 from March 2.

The streets of Daegu have been largely deserted for days, apart from long queues at the few shops with masks for sale.

Mask manufacturers have increased their total output to around 10 million a day, but availability remains limited and the government said it will ban people from exporting face coverings.

On Monday, a widowed US Forces Korea military dependent living in Daegu tested positive for Covid-19. She was the first infection connected to USFK, which has about 28,500 American troops on the Korean peninsula.

The patient, a 61-year-old woman, visited the Camp Walker Post Exchange on February 12 and 15. South Korean and American military health professionals are actively conducting contact tracing to determine whether any others may have been exposed, USFK said in a statement.

Asian countries anxious over virus, want China flight ban: new poll

USFK has raised the risk level to “high” for American military personnel on the peninsula and urged its soldiers and dependents to limit non-mission essential in-person meetings, gatherings, and temporary duty travel and assignments.

A number of political and cultural events in South Korea this week have been cancelled, while the culture ministry said on Monday a total of 24 national museums and libraries will temporarily close.

The National Assembly called off a government questioning session slated for Thursday afternoon as at least three lawmakers underwent a check after coming in contact with an education official who tested positive.

Additional reporting by Bloomberg, Reuters and Park Chan-kyong