MOSCOW, December 26. /TASS/. Nine people who were injured when a bus ploughed into a pedestrian underpass in western Moscow on Monday remain in hospitals, a source in the city medical services told TASS.

"On Tuesday morning, nine people who were hospitalized yesterday remain in the city hospitals. All of them have received various injuries, their condition is assessed as grave and moderately severe," the source said.

The bus veered off the road and plunged into a crowded underground walkway at around 14:50 on Monday near Slavyansky Boulevard metro station, killing four people and leaving another eleven injured. Nine people were sent to hospitals and two others were provided with medical assistance on the scene. One of the killed was a twelve-year-old girl.

Police ruled out a terror attack, saying they suspected a malfunction of the bus or that the driver had lost control of the vehicle.