SEOUL--South Korea reported more virus cases Friday and declared a “special management zone” around a southeastern city where the surging outbreak, largely linked to a church in Daegu, threatens to overwhelm the region’s health system.

In the capital, Seoul, officials banned major downtown rallies and shut down a big park to avoid mass public gatherings where the virus could spread. Workers in protective gear also sprayed disinfectant in the city’s subway.

Health authorities reported 52 new cases of the illness, raising South Korea’s total to 156, most of them since Wednesday. The spike, especially in and around Daegu city, has raised fears the outbreak is getting out of control in the country.

And the first two cases were confirmed in South Korea’s 600,000-member military, a navy sailor and an army officer who had both reportedly visited Daegu recently.

Prime Minister Chung Se-kyun said in a televised statement the central government will concentrate its support to the southeastern region to ease a shortage in sickbeds, medical personnel and equipment.

“A month into the (COVID-19) outbreak, we have entered an emergency phase,” Chung said. “Our efforts until now had been focused on blocking the illness from entering the country. But we will now shift the focus on preventing the illness from spreading further in local communities.”

The surge of infections in Daegu and several cases in Seoul with unclear infection routes forced government officials to acknowledge Thursday for the first time that the virus was circulating in the local population.

Initial cases of the illness in South Korea had been connected to China, where the virus has infected 75,000 people and caused more than 2,200 deaths. South Korea on Thursday reported its first virus-related death, one of 11 outside mainland China.

Daegu Mayor Kwon Young-jin on Thursday urged the city’s 2.5 million people to stay home and wear masks even indoors if possible.

Officials on Jeju Island said a 22-year-old navy sailor based on the island tested positive for the virus on Friday, days after visiting Daegu for a vacation. The sailor, currently hospitalized at a civilian hospital on the island, is Jeju’s first virus patient. The Jeju provincial office said in a statement said officials convened an emergency meeting Friday to discuss how to prevent the spread of the disease.

The Defense Ministry said the sailor is also the first virus case in South Korea’s military. Other sailors who were in contact with him at the Jeju base were placed under quarantine and all other soldiers there were also ordered to wear masks, according to a ministry statement.

Later Friday, North Chungcheong Province governor Lee Si-jong told reporters that a 31-year-old army officer based in the central province also tested positive for the virus.Lee said the officer has been sent to a military hospital and is in relatively stable condition. The officer also visited Daegu recently, according to South Korean media.

Defense Minister Jeong Kyeong-doo ordered military officials to closely coordinate with health authorities to prevent the virus from spreading inside the military and work out special quarantine steps. Jeong also ordered the military to restrict all enlisted troops from vacationing and meeting visitors from outside, according to his ministry.

Most of the new cases in the southeastern region are linked to a church in Daegu.

The Shincheonji church, which claims about 200,000 followers in South Korea, said it has closed all its 74 sanctuaries around the nation and told followers to instead watch its worship services on YouTube. It said in a statement that health officials were disinfecting its church in Daegu. The Daegu church has about 8,000 followers.

Shincheonji, which translates as “New heaven and new Earth,” is a controversial new religious movement established in 1984 by Lee Man-hee. The church describes him as an angel of Jesus sent to testify about the fulfilled prophecies of the Book of Revelation.

President Moon Jae-in ordered swifter action to trace those who recently visited the Daegu church and a hospital in another southeastern city of Cheongdo, where many virus cases were also reported in the past three days. Moon cited an examination of visitors’ books at hospital funeral halls, according to Moon’s office.

Seoul Mayor Park Won-soon said Friday that the city will keep the Seoul branches of the Shincheonji Church of Jesus closed until the outbreak comes under control. He said authorities will close some 3,500 senior welfare centers across the city, saying that COVID-19 poses a greater health risk for the elderly or those with existing medical condition.

The World Health Organization said the jump in cases in South Korea doesn’t signal an increased risk of a global pandemic. WHO Director-General Tedros Adhanom Ghebreyesus said the new cases were mostly linked to known, existing clusters of infections and that South Korean authorities were following them very closely.

“The number of cases is really manageable, and I hope South Korea will do everything to contain this outbreak at this early stage,” he said.

He noted that more than half of the COVID-19 cases outside China are from the Diamond Princess cruise ship docked in Japan.