The vehicles collided on Wednesday evening after one of the truck’s wheels burst, causing the driver to cross into the wrong lane.
Two Russian and three Kazakh citizens were among the victims.
The sixth victim has yet to be identified, a local deputy police head told TASS.
Russian, Kazakh, and Tajik citizens were among the injured, and have been taken to hospital.
Police have opened an investigation into the incident.
The bus was carrying a total of 43 passengers at the time of the crash.