A pilot and two passengers believed to be Russian nationals have been killed in a small plane crash in western Germany.

Axar.az reports that, Russia's S7 Airlines identified one of the victims as its co-owner, Natalia Fileva.

"On March 31, 2019, S7 Airlines shareholder Natalia Fileva was killed at the age of 55 during the descent in a private Epic-LT plane to [a] Frankfurt airport. The cause of the tragedy is not yet known,” the company said in a statement.

The 55-year-old was listed in 2018 by Forbes magazine as the fourth richest women in Russia with an estimated fortune of $660 million (€534 million).

The small six-seater plane the victims were in crashed into an asparagus field south of the German city of Frankfurt around 3:30 p.m. local time (1330 UTC).

A police spokesman in the central German state of Hesse said the plane came down near Egelsbach, 22 kilometers (13 miles) south of Frankfurt, and then caught fire.

Police car crashes en route

Fileva's father and the pilot are believed to be the other two people who were on board the aircraft, according to Russian media. A police statement said the passengers would most likely be identified only in the coming week.

German air traffic control said the plane had departed from Cannes, France.

The tragedy was compounded by a road accident near the airplane crash site in which two young people lost their lives.

A police car, which was rushing to the scene of the plane crash, collided head-on with another car.

Three occupants in the police car were injured. The two dead were travelling in the other car.