More than 200,000 people were being checked for coronavirus symptoms by South Korean authorities Wednesday, as US commanders reported the first case among American forces in the country.

Most of South Korea's novel coronavirus are linked to a church.

A worker wearing protective gear sprays disinfectant as part of preventive measures against the spread of the COVID-19 coronavirus, at a railway station in Daegu on February 26, 2020. (Photo: AFP)

After days of mounting public anger, the group handed over a list of 212,000 members, the government said.

Local authorities across the country -- which has more coronavirus cases than anywhere else outside China -- will check if they have symptoms of fever or respiratory disease and put them in quarantine at home if so, said vice health minister Kim Gang-lip.

A 61-year-old female member developed a fever on February 10, but attended at least four church services in Daegu -- the country's fourth-largest city and the epicentre of the outbreak -- before being diagnosed.

The Korea Centers for Disease Control and Prevention (KCDC) reported 284 new infections Wednesday -- its largest daily increase to date --  taking the overall national tally to 1,261, with the death toll rising to 12.

The vast majority -- more than 80 percent -- of Wednesday's new infections were in Daegu and the neighbouring province of North Gyeongsang, which between them account for the bulk of the national total.

An American soldier stationed at Camp Carroll 30 kilometres (19 miles) north of Daegu tested positive for the virus, commanders said, the first infection among the 28,500 troops Washington stations in the South Korea.

The 23-year-old serviceman had been put in self-quarantine at his home, US Forces Korea said, adding it was conducting "contact tracing" to determine whether other soldiers had been exposed.

The streets of Daegu -- population of 2.5 million -- have been largely deserted for days, apart from long queues at the few shops with masks for sale.

Authorities have urged the public to exercise extra caution, advising citizens to stay home if they have a fever or respiratory symptoms. 

Scores of events have been cancelled or postponed as the outbreak has spread in the world's 12th-largest economy, from K-pop concerts to the start of the K-league football season and the World Team Table Tennis championships, while museums and other public venues have closed.

In Daegu, Prime Minister Chung Sye-kyun told a meeting the government would "mobilise all resources and means" to try to control the outbreak.