Novel coronavirus infections have spread nationwide from a church in the South Korean capital, raising fears that one of the world’s virus mitigation success stories might yet suffer a disastrous outbreak, a top health official said on Thursday. The Korea Centers for Disease Control and Prevention (KCDC) reported 288 new cases as of midnight on Wednesday, marking a week of triple-digit daily increases, but offering a ray of hope in that there was no surge from the previous day’s tally of 297. Overall, South Korea has reported 16,346 cases of the coronavirus with 307 deaths. The latest outbreak has been driven by hundreds of cases in a church run by a radical conservative preacher whose followers have also attended anti-government protests in central Seoul in recent weeks, seeding infections there too. “The reason we take the recent situation seriously is because this transmission, which began to spread around a specific religious facility, is appearing nationwide through certain rallies,” Vice Health Minister Kim Gang-lip told a briefing. Authorities have tested 3,263 members of the congregation, of whom 630 have tested positive, Kim said. Hundreds more church members are being traced for testing. Another 53 infections, including 33 from the church, have been linked to the anti-government rallies in Seoul which drew thousands of people. The positive cases from the rallies include people from nine different cities and provinces across the country. Kim did not identify those places but said 114 facilities, including the places of work of infected people, were facing risk of transmission. “This is a grave situation that could possibly lead to a nationwide pandemic,” Kim said. The southern city of Busan on Wednesday reported two cases linked to the protests in the capital. The government has banned in-person church meetings in Seoul and surrounding areas – an urban sprawl with a population of 25 million – and ordered other high-risk locations including nightclubs, karaoke bars, buffets and cyber cafes to close. South Korea was one of the first countries outside China to see an explosive spread of the coronavirus early this year but it used intensive tracing and testing to bring it under control and to beat back a series of subsequent spikes. Authorities say if the number of infections rises or continues at the current rate, they will likely impose the highest level of social distancing rules, closing schools, getting employees to work from home and limiting gatherings to 10 people.