More than 300 students in Namibia have caught coronavirus since schools reopened.
The ministry of health says most cases are in boarding schools.
Health Minister Kalumbi Shangula said safety guidelines should be followed to stop transmissions in closed areas like schools.
Local media reported a coronavirus outbreak in one of the schools in Oshikoto region, which has the highest number of confirmed cases.
Namibia closed schools in March because of the pandemic and reopened them in June, with the authorities citing an absence of local transmissions.
All teachers and students were to wear masks at all times to prevent the spread of the virus. Schools administrators were also to ensure high hygiene levels.
Namibia has so far confirmed 11,373 coronavirus cases with 123 deaths.
BBC