Images from the scene showed a police car with its windscreen smashed and a number of officers in riot gear.

There were also dozens of members of the public gathered at the crash site on Snowden Road in Ely.

Scenes livestreamed on YouTube showed youths throwing fireworks and other missiles at a line of officers with riot shields who were blocking one end of the street.

A fire was burning and a helicopter could be heard hovering overhead.

South Wales Police said on Twitter that a large number of officers were working to "de-escalate ongoing disorder".

The force said its officers had arrived after the crash had taken place.

The public were warned that the road was closed between Wilson Road and Jackson Road and were urged to avoid to area.

The force wrote: "Shortly after 6pm, we received a report of a serious road traffic collision on Snowden Road. Police responded to this collision, which had already occurred when officers arrived.

"We need to ensure that this evening's collision is effectively investigated.

"Officers remain on scene to manage a large-scale disorder. Again, we urge anyone involved or watching to leave immediately.

"We understand the concern from local residents and we ask you to stay indoors."