At least four people have been killed and 15 injured after a bus crashed into an underground passageway in Moscow.
Moscow police said both passengers and passers-by were killed.
The cause of the crash was not known.
Photos taken at the scene show the bus on the steps leading underground.
Police immediately ruled out the possibility of it being an attack, saying they suspected a mechanical fault or that the driver lost control of the vehicle. Police were questioning the driver.
Russian news agencies quoted Moscow mayor Sergei Sobyanin as saying that he had ordered all city buses to be checked in the aftermath of the crash.