AKIPRESS.COM - A drone carrying small traces of a radioactive material was found on the roof of Japanese Prime Minister Abe's office Wednesday morning, police said.

A member of the Prime Minister's staff spotted the four-propeller, 50-centimeter wide drone and alerted authorities, the Tokyo Metropolitan Police said.

The drone was equipped with a small camera and a plastic bottle containing small traces of a radioactive material, according to Japanese media, citing police.

The radioactive material is likely caesium, a soft metal, harmless to the human body, police told Japanese news network NHK.

Prime Minister Abe was not in his office at the time. He is in Indonesia, attending the Asian-African Conference.