More than 100 South Korean schools have canceled or shortened classes over fears that rain falling across the country may include radiation from Japan's stricken nuclear plant.
The Education Office of Gyeonggi province says it allowed schools to decide whether to open Thursday.
The prime minister's office says radiation levels in the rain are low and pose no health threat.
Still officials say that 126 schools in Gyeonggi province shut down and 43 others shortened class hours as a precaution. The province is near Seoul.
The Ministry of Education, Science and Technology says only a few schools outside Gyeonggi canceled classes Thursday.
Nuclear safety experts has said that radiation leaking into the air and water from Japan's crippled Fukushima Dai-ichi nuclear complex do not pose a health threat outside the evacuation zone around the plant, which now stands at 12 miles (20 kilometers).
Recent progress at the plant _ which was damaged by a March 11 tsunami _ appears to have slowed the release of radiation into the ocean. This week, technicians there plugged a crack that had been gushing contaminated water into the Pacific. Radiation levels in waters off the coast have fallen dramatically since then.