Local provinces and cities on Thursday scrambled to check followers of a secretive religious sect residing in their jurisdictions for potential COVID-19 infection.

From Seoul to Jeju Island, public servants were mobilized to contact all those on the membership list of the Shincheonji Church of Jesus, earlier provided by the church, to ask whether they have shown any symptoms.

According to the sect’s Daegu branch, 8 in 10 followers who underwent the virus test have been confirmed to be infected.

Shincheonji’s Daegu church is at the center of Korea’s outbreak, with a majority of all cases traceable to its packed Sunday worship services. This made tracking down Shincheonji followers and their close contacts a top priority in the country’s struggle to contain the virus.

In Daegu, the number of infected worshippers stood at 833 as of 8 p.m. Wednesday, or 82 percent of the 1,016 tested. There were 832 others awaiting their results.

“I expect that the number of patients will continue to grow for a few days, as we have been giving priority to those who have symptoms or who want to undergo a test voluntarily,” Daegu Mayor Kwon Young-jin told reporters during a briefing.

In total, Daegu reported 1,132 cases as of Thursday evening, accounting for 64 percent of 1,766 cases confirmed across the country.

As cases in other regions show that church members infected one another and then fanned out around the country, health authorities are expanding their investigations.

On Thursday, the government received the contacts of 65,000 people taking required courses to join the sect, not included on the list of 212,000 followers submitted earlier. That brings the total in the Shincheonji group to over 310,000.

Shincheonji also released the full list of some 1,100 locations and addresses of church branches and training centers on its homepage.

“Previously, Shincheonji said that the course-takers are not yet believers, so they have difficulty in providing a list,” Vice Health and Welfare Minister Kim Kang-lip said.

Wednesday’s list was distributed to local governments, and each region has begun to screen people in the high-risk group.

Gyeonggi Provincial authorities reported that 215 people in the region said they had symptoms of the virus during a phone survey conducted on 4,890 residents who attended a service at the Gwacheon headquarters of the Shincheonji Church of Jesus on Feb. 16.

On Jeju Island, 35 Shincheonji members were found to have symptoms of fever, cough and sore throat.

Among 649 members residing on the island, 607 have been contacted by Jeju officials, but 39 remained out of touch.

“We will thoroughly manage Jeju residents who visited Daegu and North Gyeongsang Province and those who couldn’t be reached will be identified and managed with the cooperation of police,” Jeju Gov. Won Hee-ryong said.

Critics have alleged that the sect’s secretive nature allowed the virus to go undetected, and such characteristics hinder ongoing efforts to track down people exposed to COVID-19.

On Thursday, a group of people who claimed to be victims of Shincheonji filed a complaint with the Supreme Prosecutors Office against the church’s founder Lee Man-hee for violating the infectious disease prevention law, as well as other charges that include embezzlement and breach of trust.

The group, which calls itself the National Solidarity for Victims of Shincheonji, claimed the church intentionally reported a smaller number of followers and locations for services to health authorities.

“They have been obstructing epidemiological investigations in fear of exposure of the church members and to protect the organization without regard for community transmissions,” it said in the complaint.

Citing a report from a YouTube channel, the anti-Shincheonji group said the sect has 429 sites of disguised churches and secret propaganda centers that remain under the radar. A list of 70,000 trainees and key figures of the group has also not been disclosed, it said.

By Park Han-na (hnpark@heraldcorp.com)