Home Secretary Priti Patel has condemned the "disgraceful" scenes in Swansea after dramatic footage captured a vigil descending into violence.
South Wales Police urged residents to stay indoors on Thursday night as they dealt with the disorder.
Rioters were filmed setting cars on fire in the middle of the road as crowds cheered when a vehicle rolled down a hill backwards.
Officers suggested the incident in Waun-wen Road began as a vigil to a local person who recently died.
"Absolutely disgraceful scenes in Swansea last night. My thoughts are with Mayhill residents who had to endure such shocking behaviour," Ms Patel said on Twitter.
"Thank you to the brave officers at South Wales Police for bringing it under control.
"Police have my backing to take robust action against those involved."
Residents were asked not to return to the Mayhill area of the city as police warned those involved should expect to face "robust action".
Wales’s First Minister Mark Drakeford described the violence as "completely unacceptable" and said the disorder would "not be tolerated anywhere in Wales".
He also thanked police officers for bringing the incident under control.
South Wales Police’s Chief Constable Jeremy Vaughan said the force would "stop at nothing" to find those responsible.
"Saddened and furious at events in Swansea last night," he tweeted.
"So many families will have been tormented by those responsible, rest assured we @swpolice will stop at nothing to find them.
"We will work hard with others to help and support local residents who deserve better than this."
Swansea Council said it was "responding at pace" to the disruption, with officers assisting with "clean-up operations, helping with repairs and reassuring residents".
Councillor Rob Stewart, the leader of Swansea Council, called it "absolutely disgusting behaviour by yobs".
South Wales Police said there would be an increased police presence in Mayhill over the weekend after describing the incident as "totally unacceptable".
Assistant Chief Constable Jenny Gilmer said: "These are scenes we don’t expect in our communities and our officers should not expect to have to confront situations like this."
She added: "Our focus now is to fully investigate this appalling incident. We will be using CCTV and social media footage to help us to identify and arrest those responsible.
"The level of violence towards emergency services and the damage to buildings and vehicles was totally unacceptable."
Anyone with information, photographs or video footage is asked to contact South Wales Police, quoting incident 992 of 20 May