Tokyo, April 24 (IANS): Japanese authorities have closed a park in Tokyo after detecting high levels of radiation believed to be emanating from material buried there, media reported on Friday.

The park is located near Shimoitabashi station in a residential area of Toshima district in northern Tokyo.

Police have closed and barricaded the park as authorities search for the source of the radiation near the children's playground, according to Efe news agency.

A high level of radiation of up to 480 microsieverts per hour was detected in the area on Thursday, a government spokesperson told the Kyodo news agency.

That hourly dosage level is almost half the maximum annual dose of 1,000 microsieverts considered safe for an average person.

The detection occurred two days after a drone containing radioactive cesium was found on the roof of Japanese Prime Minister Shinzo Abe's residence.

Given that the isotopes detected in the drone are not found in nature and are a product of nuclear fusion, authorities believe they could be the result of emissions released during the 2011 Fukushima nuclear power plant disaster.