Authorities in the Japanese capital of Tokyo have cordoned off a playground where high levels of radiation were detected this week, reviving concerns about nuclear contamination four years after the Fukushima disaster.
Nuclear regulators measured elevated radiation levels on 23 April in a children's park, city officials said, more than 250km from the crippled Fukushima nuclear plant in northeast Japan.
One area of the park registered 480 microsieverts per hour, or nearly half the recommended annual limit of exposure.
That compares with radiation levels ranging from 0.7 to 23.2 microsieverts per hour measured this month in the air in Okuma, a town less than 20 km from the Fukushima plant.
It was not immediately clear why radiation levels were high in the park, which opened two years after the 2011 disaster. It has now been fenced off with an orange barricade, the city said.
A representative of Tokyo's Toshima ward said radiation levels in other parts of the park remained low.
A drone with a small amount of radiation was found on Japanese Prime Minister Shinzo Abe's office building this week.