Trace amounts of radioactive substances have been found in urine samples taken from children from Fukushima city, raising concerns that residents have been exposed internally to radiation from the strickennuclear power plant 37 miles (60km) away.
Tests were conducted in May on 10 children, aged between 6 and 16, by a Japanese civic group and Acro, a French body that measures radioactivity. All 10 tested positive for tiny amounts of caesium-134 and caesium-137.
The chief cabinet secretary, Yukio Edano, said he was concerned by the findings and the government would thoroughly examine the results.
Demonstrators pass the headquarters of Tokyo Electric Power Co, the operator of tsunami-hit Fukushima Daiichi nuclear plant, during an anti-nuclear power protest in Tokyo on Thursday. Photograph: Shizuo Kambayashi/AP