South Korea reported its second highest number of daily new COVID-19 cases ever on Wednesday, just days after it began easing social distancing restrictions in some parts of the country, buoyed by an accelerated vaccine rollout.

With the majority of the 1,212 new cases coming from densely populated Seoul, officials extended movement curbs in the capital and surrounding regions for at least another week and are considering pushing restrictions back up to the highest level.

Prime Minister Kim Boo-kyum said the country's fourth wave of the virus, fueled by the highly contagious delta variant, was spreading rapidly, especially among unvaccinated people in their 20s and 30s.