Riot police are at the scene of a major incident in Cardiff following a serious crash in the Ely area of the city.
Emergency services reported being at the scene on Snowden Road on Monday evening which later escalated into what police described as a "large scale disorder".
A large crowd of people gathered, many wearing balaclavas and face masks, and were seen throwing objects at police and their vehicles.
The road is closed between Wilson Road and Jackson Road and police have asked members of the public to avoid the area.
A police helicopter, riot police and dogs are at the scene.
Officers from across south Wales were brought in to respond to the incident, with dozens of riot police lining up across a road as objects were thrown towards them.
Pictures from social media show a police vehicle with its front window smashed and broken wing mirrors.
A group of people were also seen throwing a door towards riot police and a car was also set alight just before midnight.
Families with young children were seen in the street watching the disorder, but later the numbers reduced – although dozens stayed, many covering their faces.
A second car was then targeted as several people tried to push it into the burning vehicle, but ended up turning it over.
The scenes were broadcast live across social media on Facebook, YouTube and Instagram.
South Wales Police said shortly after 6pm, it 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 evenings 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."
"I'm worried sick"
One resident told ITV News, "It's terrible, I've got my son who lives in Stanway Road with four kids and I've had to phone my daughter in Stanway Place where it all kicked off. I'm worried sick - I'm going to be up all night.
"I haven't seen anything like this for many years - not since last riots here about 20 years ago".
There were items on fire in the road, with riot police with shields the other side of them.
A large number of objects were thrown at police with people gesticulating at officers carrying riot shields.
Cardiff Bus said its services have been diverted due to the ongoing incident.
Police urged people to 'avoid speculation". It said, "Please avoid speculation – we will bring you the latest details as soon as we can - all of our updates must be factual."