A tour helicopter crashed Saturday afternoon in the Grand Canyon in Arizona, killing all seven people aboard including three Japanese, according to the local sheriff's office.

The three Japanese were two female tourists and a pilot, the office said. One of the two females was identified as Akiko Hatano, and the other as Masami Kato, both from Kanagawa Prefecture.

The helicopter, owned by Las Vegas-based Sundance Helicopters Inc., went down 80 km northeast of Kingman, Ariz.

It crashed as it was descending to the floor of the canyon, the Associated Press quoted Federal Aviation Administration spokesman Diana Joubert as saying.

The cause of the accident was not immediately known.