At least three dead and six injured after bus plunges off bridge into river in Russia

 (AFP via Getty Images)
(AFP via Getty Images)

A bus has plunged into a river in Russia leaving at least three three dead as police launched a criminal investigation into the incident.

The vehicle ploughed through a barrier and into the water in St Petersburg, city officials said.

The Emergencies Ministry said that rescuers removed nine people from the water and three of them died.

It said that four others were in a critical condition and two more were in a serious condition.

Russian news reports said there were 15 people on the city bus when it veered from the road into the Moika River in central St Petersburg on Friday.

Six of those who were onboard climbed out of the water on their own, according to local reports.

A surveillance video released by Russian media showed the bus travelling at speed, making a sharp turn on to the bridge and colliding with another vehicle before breaking through the barrier and plunging into the water.

Authorities in St Petersburg said that the owner of the bus had been fined 23 times for various violations.

They are investigating potential traffic violations and unsafe travel services, in connection with the river deaths.

Private companies run most of the city's bus services.

The bus driver was detained by police.

His wife was quoted by Russian media as saying that managers forced him to work a morning shift after working for 20 hours the previous day and getting virtually no rest.

Authorities opened a criminal investigation into alleged traffic violations and unsafe travel services.