A bus left a road in Moscow before ploughing into a subway entrance, leaving at least Five people dead and 15 injured, Russian media say.
CCTV video shows people scattering as the vehicle ran down the subway’s wide steps before being brought to a halt by the tunnel’s roof.
The incident occurred near Slavyansky Bulvar metro station in western Moscow.
The cause of the incident was not immediately clear but there was no suggestion it was a terror attack.
Another vehicle may have hit the bus or its brakes may have failed, an unnamed source in the emergency services told Ria-Novosti news agency.
According to another unnamed source, quoted by Interfax news agency, technical failure was the likeliest cause.
A preliminary examination showed the driver of the bus was sober, it added.