After imposing tough restrictions on the capital Seoul, South Korea is now extending those measures to the entire country.
Health officials reported 315 new coronavirus cases on Friday – the second rise exceeding 300 in as many days.
For a country used to daily infection figures below 20, it has come as a shock, says the BBC’s Laura Bicker in Seoul.
The current outbreak originated in a church whose members took part in a mass rally in Seoul last week, despite pleas from the government for them to stay at home.
Among the measures coming into force on Sunday are restrictions on large gatherings, a ban on in-person church meetings, and the closure of nightclubs, karaoke bars, buffets and internet cafes.