© Thomas Peter/ReutersOfficials carry a blue box reportedly containing a drone from the rooftop of Shinzo Abe’s offices in Tokyo.
Traces of radiation reportedly detected on drone carrying camera and bottle with unidentified contents

Japanese authorities have launched an investigation after a small drone reportedly containing traces of radiation was found on the roof of the prime minister's office, sparking concerns about drones and their possible use for terrorist attacks.

No injuries or damage was reported from the incident on Wednesday. The prime minister, Shinzo Abe, who is at present in Indonesia, works at the building during the day and commutes from his own private home roughly 15 minutes away.

Police said it was not immediately known who was responsible for the drone.

The significance was not immediately clear, but a Japanese court on Wednesday approved the restart of a nuclear power station, rejecting nuclear power safety worries in the wake of the 2011 Fukushima radiation disaster.

The chief cabinet secretary, Yoshihide Suga, said the incident was a wakeup call to the potential dangers of drones, including possible terror attacks when Japan hosts the 2020 Olympic Games in Tokyo.

It was not clear when the drone landed. It was found on Wednesday by an official who was reportedly taking new employees on a tour of the prime minister's office in central Tokyo.

© The Asahi Shimbun via Getty ImagesInvestigators check a drone, under tarpaulin, on the roof of the prime minister’s office. The camera-equipped drone produced a low level of radiation, police said.
Japanese media reported that investigators detected small traces of radiation from the drone, presumably not levels harmful to humans. TV footage showed several uniformed policemen without hazmat suits carrying a blue plastic box containing the drone for further examination.

Video from public television broadcaster NHK earlier showed dozens of police officers and officials around the drone, which was covered by a blue tarpaulin.

The drone was about 50cm in diameter and had four propellers, carrying a small camera and a plastic bottle with unidentified contents inside, according to Tokyo's Metropolitan police department. The drone was also decorated with a symbol that warns of radioactive material, according to NHK.

Small drones are becoming increasingly popular in Japan and are often used for performances, aerial filming and other purposes, but have been raising safety concerns.

In the United States in January, a wayward drone flown by an off-duty intelligence employee crashed on the White House grounds, raising questions over how commercial and consumer drones can be used safely in the US.

Japanese aviation laws have no restrictions for flying unmanned equipment at or below 250 metres above ground except for flight routes.

Source: The Associated Press