Police have promised “robust action” against rioters who torched cars and hurled bricks through windows after a vigil for a teenager exploded into violence in the south Wales city of Swansea. Families were trapped inside houses and rioters threw rocks at police as they tried to break up the disorder in the Mayhill area of the city on Thursday night. Seven officers suffered minor injuries – mostly from missiles being thrown – but did not require hospital treatment. Jeremy Vaughan, the chief constable of south Wales police, 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 will stop at nothing to find them. “We will work hard with others to help and support local residents who deserve better than this.” The Welsh first minister, Mark Drakeford, said: “The violent scenes in Swansea last night were completely unacceptable and will not be tolerated anywhere in Wales.” He thanked the police “for bringing the situation under control and continuing to monitor it closely this morning”. It is believed the violence broke out at a vigil for local 19-year-old Ethan Powell, who collapsed hours after watching Swansea City’s play-off football match against Barnsley on television on Tuesday. The cause of his death is unknown. Members of his family said they were horrified at the violence and said the teenager would have tried to stop it. About 100 people were involved in the incident. Crowds cheered and screamed as cars were set alight and pushed down a hill. Police warned people to stay indoors. South Wales police assistant chief constable Jenny Gilmer said on Friday: “What occurred last night was absolutely unacceptable and something that we rarely see here on the streets of south Wales. “We are still trying to understand what the trigger point or catalyst was.” Alun Michael, south Wales’ police and crime commissioner, said: “The scenes we witnessed in Swansea last night were totally unacceptable and I was extremely saddened to hear that some officers called to the incident were injured, though thankfully not seriously. “I’m extremely grateful for the immediate actions taken by the police and our partners to these events and it was also heartening to hear that off-duty officers volunteered their time in support of colleagues and the safety of the local community. “It is now critical that those responsible are identified and held to account for their actions.” The home secretary, Priti Patel, described the scenes as “absolutely disgraceful”. The Welsh secretary, Simon Hart, said: “A tough night for the police dealing with such reckless behaviour. No excuses, police right to robustly respond.” Rob Stewart, the leader of Swansea council, said: “This is completely unacceptable and inexcusable behaviour. Our thoughts are with the residents who have had to put up with this utterly despicable behaviour in our community. “We will support the police to identify, pursue and prosecute those that have organised and participated in this criminal activity.” Crowdfunding pages have been set up to help those whose homes and cars were damaged. One of the fundraisers, Sophie Heneberry, said: “As a city, I think we’re all shocked and speechless by the acts of those involved. The thoughtless and selfish behaviour of those who decided to riot amongst the streets of Mayhill have a lot to answer for.”