In Tokyo, a scare involving a radioactive drone.

Details from Tokyo and FOX News Radio's Alastair Wanklyn:

The drone quadcopter found on the roof of the Japanese prime minister's office -- it had a camera, a bottle with liquid and a label warning it was radioactive.

Tests found it was, slightly.

Prime Minister Shinzo Abe not in the building at the time, but the government here calling for... better security.

There's no word if the drone was an attack or a stunt by activists, such as those who say radioactive fallout from the Fukushima disaster shows nuclear power is not worth the risk.

In Tokyo, Alastair Wanklyn, FOX News Radio.