A small drone, which contained a camera and radioactive material, was found Wednesday morning on the roof of the office of Japanese Prime Minister Shinzo Abe in Tokyo. The drone was reportedly found by an official at the office who reported it to the police.

Police are now investigating the drone and looking for its owner. No injuries or damages have been reported due to the incident. Abe is currently in Indonesia for an Asian-African conference, the Associated Press (AP) reported. 

It is unclear who sent the drone and when it landed on the rooftop. While initial reports suggested that the drone was a mishap, a thorough investigation was ordered after authorities found traces of radiation. The drone was about 50 centimeters (1.7 feet) in diameter and had four propellers. The device reportedly had a radiation symbol on it.

Footage recorded by NHK, the state-run network, showed officials in hazmat suits, gathered on the rooftop, placing a blue cover over the drone. Officials said that the trace amounts of radiation, found from the drone, were not up to the level of causing harm to humans, the AP reported. Authorities are also investigating if the drone crashed during a flight.

The discovery of a drone on top of the five-storey building has highlighted the lack of regulations in the country, where drones are gaining popularity and are available in several shops, the Japan Times, a local newspaper reported. According to Japan’s transport ministry, a person operating the drone needs to inform authorities if they plan to fly it at an altitude of 250 meters or higher. But the regulations do not apply for flights at lower altitude, except for areas near the airport or within the flight routes of other planes.

In January, a wayward drone, which was being operated by an off-duty intelligence employee, crashed on the White House grounds in the United States. The incident sparked off a debate on how drones could be used safely for commercial and consumer use.