Russian investigators say all nine people aboard a helicopter and a seaplane were killed when the aircraft collided over a water reservoir near Moscow.

The Armenian Embassy said four citizens of Armenia, including two children, were among the dead. Russian Channel One state television said one of its journalists also was killed.

The Cessna 206 and Robinson 44 helicopter collided over the Istra reservoir Saturday night. By Monday morning, investigators said divers had recovered eight bodies, while the search for the ninth victim was continuing.

The federal Investigative Committee said the accident appeared to have been caused by pilot error.

The seaplane was used to take people for rides over the reservoir, which is 22 kilometers (13 miles) long and up to 2 kilometers (1.2 miles) wide.