South Korea on Friday confirmed 52 more cases of novel coronavirus as the number of infections linked to a religious sect in Daegu spiked, making it the worst-infected country outside China.

Thirty-nine of the new cases were linked to the Shincheonji Church of Jesus in the southern city of Daegu, the Korean Centers for Disease Control and Prevention (KCDC) said, taking the country’s overall figure to 156.

More than 80 members of Shincheonji have now been infected, starting with a 61-year-old woman who developed a fever on Feb. 10 but attended at least four church services before being diagnosed.

The mayor of Daegu — South Korea’s fourth-biggest city, with a population of over 2.5 million — has advised residents to stay indoors. Access to a major U.S. base in the area has been restricted.

Residents wore masks while going about their daily activities Friday, but the streets remained active.

Outside the Shincheonji church, Seo Dong-min, 24, said, “With so many confirmed cases here, I’m worried that Daegu will become the second Wuhan,” the Chinese city where the virus first emerged.

Shincheonji is often accused of being a cult.

It 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.

Officials at the Daegu Municipal Government said 1,001 Shincheonji members believed to have attended services with the infected woman have been asked to self-quarantine themselves.

The KCDC said one more case had been confirmed at a Cheongdo county hospital near Daegu where a total of 16 infections have now been identified, including a long-stay patient who died Wednesday after showing symptoms of pneumonia.

It is investigating whether the original Shincheonji patient was linked to the hospital cluster, as she visited Cheongdo earlier this month.

On Friday the central government declared Daegu and Cheongdo “special management zones.”

Seoul will support the region with medical personnel, sick beds and equipment, Prime Minister Chung Sye-kyun said, and the Cabinet will meet three times a week on the outbreak.

The U.S. Army garrison in Daegu — where around 10,000 soldiers, civilians and family members live or work — has restricted access and instructed any American troops who recently attended Shincheonji services to self-quarantine.

“Travel in and around Daegu is highly discouraged unless absolutely necessary,” the garrison said Thursday in a Facebook post. “Please avoid public places and public transportation, to include stores, restaurants, subways and other heavily congested areas.”

Shincheonji has closed down all its facilities nationwide.

“We are deeply sorry that because of one of our members, who thought of her condition as a cold because she had not traveled abroad, led to many in our church being infected and thereby caused concern to the local community,” it said in a statement.