MOSCOW, July 22 (Xinhua) -- A light plane crashed Sunday in central Russian region of Ryazan, killing three people on board, regional emergencies department said.

"At 13:57 Moscow time (0957 GMT), Ryazan's regional emergencies administration received reports about the crash of a light plane in a forest near Alexandrovo district," a spokesman told local media.

Rescuers found three bodies at the crash site, including two adult men and a boy, the spokesman said, without giving their names.

There were no casualties on the ground, the spokesman said, adding that the cause of the crash remained unclear.

Ryazan's flight control center said it didn't register the flight of the plane, a single-engine Il-103 plane that is capable of carrying four people, indicating the plane took off without permission.

An investigation into the accident was still underway.