No radioactive materials have been found in rain that fell on South Korea over the weekend, despite escalating fears of radiation in Japan, the government said Tuesday.

   The Ministry of Education, Science and Technology said a thorough examination of rainwater samples collected from across the country on Sunday showed no traces of radioactive iodine or cesium.

   "There was no trace of either iodine-131 or cesium-137 in any of the samples collected from the 12 radiation detection centers nationwide," the ministry said.

   Both materials are by-products of fission reactions and can cause cancer and infertility. Large doses of the radioactive materials can also lead to death.

   Tests were conducted to alleviate public concerns that radioactive materials released into the atmosphere from Japan's crippled Fukushima nuclear power station may have been absorbed by rain, it said.

   The ministry, meanwhile, said that close monitoring of radiation levels in the atmosphere showed no abnormal hikes.

   Seoul has been checking radiation levels from its 70 monitoring stations since March 12 when a reactor at Fukushima exploded. The power station located 250 kilometers northeast of Tokyo was hit by the massive earthquake and tsunami, causing critical power failure to reactor cooling systems. (Yonhap News)