South Korea warned of a second wave of the novel coronavirus as infections rebounded to a one-month high, just as authorities were starting to ease some pandemic restrictions, Reuters reports.

“It’s not over until it’s over,” President Moon Jae-in told the nation, saying a new cluster shows the virus can spread widely at any time, and warning of a second wave late this year.

The Korea Centres for Disease Control and Prevention reported 34 new infections, the highest since April 9, after a small outbreak emerged around a slew of nightclubs, prompting the authorities to temporary close all nightly entertainment facilities around the capital.