moscow passenger bus swerve course drive busy pedestrian underpass moscow monday kill least four people russian news agencies report video scene post social media show bus veer road plunge step pedestrian underpass crush several people beneath wheel driver bus detain police agencies say lose control vehicle incident occur one russian capital busy roads near slavyansky boulevard metro station monday ordinary work day russia orthodox christmas celebrate jan. 7. unnamed emergency service source tell tass news agency number fatalities rise five people also unconfirmed report 15 people injure interfax news agency say investigators look whether incident occur result technical fault bus ten ambulances fire service personnel three medivac helicopters scene agencies report bus drive pedestrian underpass moscow kill four agencies