South Korea's education chief said the number of schools that have postponed reopening due to recent clusters of COVID-19 has declined from last week's 838 to 519.

On Wednesday, Education Minister Yoo Eun-hae said when there were possibilities of schools being affected by the clusters, reopening plans were adjusted and teachers and students were tested for the virus.

While tests were conducted on some 57-thousand students and teachers, Yoo said eight students were found to have contracted the virus outside school.

The minister, however, expressed concern over clusters linked to private educational institutes in the Seoul metropolitan area, urging regional education offices to heighten quarantine and thoroughly monitor the situation in their areas.

Yoo also urged students to maintain good hygiene, return home after school and seek testing when showing symptoms.