A bus carrying 20 passengers plunged into a river in St Petersburg killing at least three people, Russian media reports, with horrifying footage showing the moment it smashed into a car and spun off the bridge.

The out of control vehicle was seen swerving wildly along the road, slamming into oncoming traffic before crashing through the bridge's fence and falling into the Moika River.

Stunned passersby ran over as the number 262 bus became submerged, with only its roof visible above the water for hours before it was lifted out by a crane this afternoon.

Emergency services rushed to the scene this morning, with authorities saying that rescuers pulled nine people from the water in a rapid operation. Three of them died, while four others were in a critical condition and two more were in a serious condition. Six more people got out themselves.

The driver has been arrested and was taken for questioning by police, with authorities saying they are still trying to establish what happened. 

The bus smashed through the bridge's barrier and plunged into the river, footage shows

Stunned passersby ran over as the bus became submerged, with only its roof visible above the water

Searches of the river are said to be ongoing after this morning's crash, with the bus remaining submerged

Rescuers lift the wreckage of a bus out of the Moyka River in St.Petersburg, Russia, 10 May 2024

Brave locals were seen jumping into the river and standing on the roof of the bus as they tried to haul victims out of the sinking vehicle.

Bystanders threw them lifebuoy rings to help in the rescue effort, while a passing boat also pulled up nearby.

It is believed that a number of people were pulled out alive through the hatch in the roof of the bus by rescuers.

Six got out on their own and then were collected by rescue boats in the Moika River, according to reports.

Reports said the driver was among those who escaped and he was immediately detained, with a criminal case opened. 

Authorities in St Petersburg said that the owner of the bus had been fined 23 times for various violations. Private companies run most of the city's bus services.

The bus driver's 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.

Witnesses at the scene suggested that the bus may have been faulty. It hit an SUV before plunging in the river, according to reports.

Rescuers work at the site where a passenger bus fell off a bridge into a river in Saint Petersburg, Russia May 10, 2024

Rescue teams on boats in the River Moika today as the bus was pulled out by a crane

The vehicle was seen swerving wildly along the road, slamming into oncoming traffic before falling into the river

Governor of St Petersburg Alexander Beglov said that a multi-agency operation was underway which he was coordinating personally.

He added that the victims of the crash were being provided with 'prompt assistance'.

The city's transport committee reported that the driver of the bus lost control when turning from Bolshaya Morskaya Street to Potseluev 'Kissing' Bridge.

'The bus turned around, it broke through the fence and fell into the water. Emergency Situations Ministry employees and an ambulance are working at the scene,' it said.

Crowds watched on as rescuers continued to search the river following the horror crash

'Representatives of the carrier and the leadership of the transport committee have also been sent to the scene. All victims will be provided with the necessary assistance.'

A witness said they saw the bus swerve before the collision. 'He started hitting cars that were parked. Everything happened quickly,' the man said of the driver.

A student called Mikhail said: 'I saw the moment the bus hit the car, it spun around and it began to fall.

'The bus went sideways, smashed the curb, smashed a fence and fell sideways.'

Another witness said: 'The driver of the bus, when turning from Bolshaya Morskaya Street to Potseluyev Bridge, lost control, the bus spun around, it broke through the fence and fell into the water.'