Police officers faced “large scale disorder” at the scene of a serious road traffic collision in Cardiff with rioters throwing missiles, including fireworks, at them.
At least two cars were set on fire as trouble flared for hours, involving scores of youths, many covering their faces with masks.
Officers were called to the scene of the crash on Snowden Road in Ely shortly after 6pm on Monday, and rioters were still on the streets nine hours later.
Police said the collision “had already occurred when officers arrived”.
Scenes being livestreamed on YouTube showed young people throwing fireworks and other missiles at a line of police officers with riot shields who were blocking one end of the street.
A fire was burning and a helicopter could be heard hovering overhead.
Shortly before midnight a car was set on fire and burned fiercely, while a second vehicle was overturned and set ablaze.
A member of the public was attacked due to rioters thinking they were an undercover officer, according to one of the senior officers at the scene.
The public were warned the road was closed between Wilson Road and Jackson Road and urged to avoid the area.
At 8.21pm, South Wales Police tweeted: “There is now a large number of officers working to manage the collision, but also to de-escalate ongoing disorder at the scene.
“We urge anyone involved to leave the scene immediately and ask local residents to stay away while the matter is brought to a safe conclusion.”
An hour later, police said emergency services remained at the scene and reiterated the importance of people staying away from the area.
The force added: “Please avoid speculation – we will bring you the latest details as soon as we can – all of our updates must be factual.”
At 11.15pm, South Wales Police provided a further update that officers remained at the scene to manage “large scale disorder”.
It added: “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.”
Police, including mounted officers on horseback, were seen outside Ely police station in the early hours of Tuesday after suggestions it could be targeted.
Shortly before 3am, rioters moved down Highmead Road in Ely, following by police who were trying to disperse them.
The rioters continued to throw missiles and set cars alight.
One resident of Highmead Road, who did not want to be named, told the PA news agency: “Enough is enough now. This has gone beyond.
“When people are making fun of what’s happening on social media it’s crossed a line.
“This is our neighbourhood and those doing this are just kids. It needs to stop.”