At least 30 people have been injured after two trams collided at Strasbourg’s central station on Saturday, authorities said.

Videos and photos posted on social media showed two trams containing dozens of people inside. One video shows smoke rising and chaotic scenes as an alarm sounds.

Local media reported that the crash occurred after one of the trams switched tracks and collided with a stationary tram. Other reports said one tram was reversing at the time.

A spokesman for the prefecture said an investigation into the cause of the accident has been opened and no fatalities have been confirmed.

Strasbourg’s mayor Jeanne Barseghian told reporters at the scene there had been a collision involving a tram, but the cause was not known.

According to BFM TV, Barseghian called on people to wait for the results of the investigation.

One eyewitness named Johan told AFP news agency that he saw one of the trams reversing at speed, adding: “We heard a big impact, a big bang.”

Another eyewitness told BFM TV that the doors of the tram flew off on impact.

The outlet reported that a large security perimeter was set up in front of the station.

The Bas-Rhin region’s Fire and Rescue Service posted on X urging people to avoid the area to allow emergency services to access the area.

The service’s director Rene Cellier said some of the non-fatal injuries reported were “mostly trauma”, but also include scalp wounds, clavicle fractures, and knee sprains.

“There are also around 100 people who have no particular injuries but are being seen by the doctors,” Cellier said.

He added that around 50 vehicles and 130 firefighters were dispatched to the scene and that the situation “could have been much more serious”.

Emmanuel Auneau, the director of the CTS – which is responsible for managing public transport in Strasbourg – said the two tram drivers were “not physically injured, but are very shocked”.