Video shows a bus falling off a bridge in St. Petersburg, Russia, killing 7 people

A bus veered into traffic, veered off a bridge and plunged into a river on Friday in Russia’s second-largest city, St. Petersburg, killing seven people, officials said.

The Investigative Committee, Russia’s highest criminal investigation body, announced the death toll. It did not specify the number of other injured people, but the Ministry of Emergencies said earlier that six people were taken off the bus in critical or serious condition.

Russian news reports said that there were between 15 and 20 people on board the city bus when it broke through a barrier and fell into the Moika River in central St. Petersburg. Six of those on board emerged from the water on their own.

Surveillance video published by Russian media showed the bus traveling at speed, making a sharp turn on the bridge, swerving across the lanes and colliding with another vehicle before breaking through the barrier and falling into the water.

One witness described bystanders jumping into the water to try to help rescue the passengers.

“They dived in with their clothes on and helped,” she said in Russian.

Authorities in St. Petersburg said the bus owner was fined 23 times for various violations. Private companies operate most of the city’s bus services.

Another witness said it looked like he was “either driving erratically or the brakes failed.”

The police arrested the bus driver. Russian media quoted his wife as saying that managers forced him to work a morning shift after he worked 20 hours the previous day and got almost no rest.

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