SEOUL — South Korea reported on Wednesday its highest daily rise in novel coronavirus cases since early March as outbreaks from churches around the capital spread, prompting a warning of a nationwide wave of infections.

The 297 new infections mark the sixth straight day of triple-digit increases in a country that has managed to blunt several previous outbreaks.

The national tally rose to 16,058 infections with 306 deaths, according to data from the Korea Centers for Disease Control and Prevention (KCDC).

Nearly 90% of the new cases appeared in the capital, Seoul, and surrounding areas, raising concern of the rapid spread of the virus in a metropolitan area of more than 25 million people.

“We’re in a desperately dangerous crisis where infections are spreading in the Seoul metropolitan area and threatening to lead to a massive nationwide transmission,” Vice Health Minister Kim Gang-lip told a briefing.

“The government cannot contain the current spread only with tracing and isolation…. Please stay home unless you must go out.”

At least 140 of the new infections are linked to the Sarang Jeil Church, taking the number of cases from it to nearly 600.

Authorities are trying to trace another 600 members of the church’s congregation, who should be in isolation and would like to test all of its 4,000 members, Mr. Kim said.

More than 8,500 police have been mobilized to track down church members, he said.

Authorities have said some members of the church, which is run by a radical conservative preacher, are reluctant to come forward and get tested, or to self-isolate.

Prime Minister Chung Sye-kyun said the government would take legal action against the church for any attempt to disrupt tracing and testing efforts by failing to provide accurate membership lists. — Reuters