A 40 - year - old Japanese man admitted he landed an unmanned drone in central Tokyo carrying Movement.Transportation.IllegalTransportation radioactive sand atop Prime Minister Shinzo Abe ' s office to protest Conflict.Demonstrate.Unspecified nuclear power , police said Saturday .

The drone , which had a sign on it saying it was radioactive , was carrying a camera and plastic container with sand contaminated with radioactive cesium , Japanese media said . The police said the radiation was low and did not pose a threat . The stunt initially brought fears of carrying Movement.Transportation.IllegalTransportation terrorist attack .