SEOUL--South Korea reported its highest daily rise in novel coronavirus cases since early March on Sunday, as outbreaks continued to spread from a Seoul church and from political demonstrations its members had attended.

The Korea Centers for Disease Control and Prevention (KCDC) reported 397 new infections as of midnight Saturday, up from the previous day's 332 and marking more than a week of daily three-digit rises.

That brings South Korea's total to 17,399 infections of the new coronavirus with 309 COVID-19 deaths, it said.

From Sunday the government imposed second-tier social-distancing rules in areas outside Seoul, banning in-person church meetings and closing nightclubs, buffets and cyber cafes.

Health authorities say they may eventually deploy the toughest stage 3 social-distancing rules, where schools and business are urged to close, if the rate of increase in new infections does not slow soon.

On social media, mothers posted notes saying they have cancelled vacation plans to nearby hotels and the southern resort island of Jeju to comply with government guidelines.

On Friday, health authorities said South Korea's coronavirus infections are back "in full swing" as hundreds of infections have started to come out from the Sarang Jeil Presbyterian Church run by a far-right preacher.

Members of the church attending an anti-government protest in Seoul on Aug. 15 have also led to new cases across the country.