Four people died when the driver of a commuter bus appeared to intentionally drive off a bridge into a river in Russia.

The incident happened on Friday in St. Petersburg.

CCTV footage shows the bus make a sharp right turn, ram a car on a bridge, then plunge into the Moika River.

The bus was almost completely submerged in the river and only the roof was visible.

Some passengers died from impact injuries when the bus hit the water.

Russian Ministry of Emergency

Rescuers cut holes in the roof to pull passengers and bodies out.

According to reports, 15 people were on the bus and all are accounted for. Six people were treated for non-life threatening injuries. Four people are in critical condition in a local hospital.

The bus driver was detained at the scene. His wife told a Russian news agency that her husband was forced to work Friday morning after working a 20-hour shift the day before without any rest.

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Authorities in St. Petersburg said the bus owner had been fined 23 times for various violations. City buses are operated by private companies.

The bus owner faces a criminal investigation for alleged traffic violations and unsafe travel services.