Tokyo police have questioned a Chinese researcher who flew a drone near Tokyo Station without authorization.
The researcher in his 50s from Beijing's transportation bureau allegedly violated Japan's civil aviation law.
He was seen flying the drone last Friday over a road from the station to the Imperial Palace in central Tokyo.
Drone flights are banned in principle over the palace and densely populated areas.
Investigators examined the drone and reportedly found images of sites including the State Guest House, where summits and other events are held.
The researcher reportedly admitted to flying the drone from a garden at his hotel.
The man was in Japan to observe subway systems. He has already returned to China.
He reportedly said he was taking photos with the drone he'd brought from China as part of his hobby, and that he was not aware of the flight ban.