Adults were encouraging children to throw items at police during the riots that broke out in Cardiff last night, a resident has claimed.
Tensions reached breaking point after police officers were called to the scene of a road accident in Ely shortly after 6pm.
Best friends Kyrees Sullivan, 16, and 15-year-old Harvey Evans were killed in the crash while riding an electric bike.
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.
Shortly before midnight a car was set on fire and burned fiercely, while a second vehicle was overturned and also torched.
One local, who lives near the scene, told Wales Online: "It was very scary what happened. All of our cars have been damaged.
"I didn’t know what they were doing to be honest. I don’t think they knew. Idiots. Absolute idiots.
"There was a lot of people. Lots of children, I was very surprised at how many children and how many adults encouraging them. They were throwing stuff at the police.
"It’s so sad. We just had to stay in and watch it. They didn’t aim at the cars specifically they were aiming at the police.
"I’ve lived here 27 years and never seen anything like that. Never. We are a close community we are so nice around here. Really really nice."
Friends of the two boys, who were from the Ely area, said they were riding a Sur-Ron electric bike without helmets when they died.
They said their families were desperate for further information from the police about what happened.
Bridy Bool, who lives nearby, said she knew the family of Harvey Evans and his mother wanted to know which hospital her son had been taken to.
“The police are not telling her where her boy is – she has been waiting all night and morning,” she said.
“They are not telling them – they are waiting for the family liaison officer. It was 2.40am when her boy’s body got moved from there. I’ve just left her house now.
“There’s no support. They are on the phone but there is no support on the ground – all this is going on and they are nowhere."
Paying tribute to one of the teenagers, she said: “Harvey was such a young boy, a sociable boy, he had loads of friends and he loved motorbikes and football.
“He was best friends with Kyrees and were into the same things. It was not unusual for them to be together."
The South Wales force said arrests have been made but did not say how many.
Specially trained public order officers were deployed, including officers from neighbouring police forces, as several vehicles were set alight, property was damaged and officers were injured.
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.
Shortly before midnight a car was set on fire and burned fiercely, while a second vehicle was overturned and also torched.
Jane Palmer, the owner of a burnt-out Ford Focus, said she and her family watched from their window as rioters set fire to her car.
Ms Palmer said: "I’m disabled so now I’m trapped without my car. Why are they doing this? It’s just silly now.”
A man called Connor, who also lives in Highmead Road, said: “It’s been a mad night. This is not the norm around here but people are pretty anti-police and that’s reflected on both sides, not that that’s my opinion.”
One person was attacked because rioters thought they were an undercover officer, according to a senior officer at the scene.
Assistant Chief Constable Mark Travis said: "First and foremost our thoughts are with families of the two boys who have died following the collision in Ely and with those affected by the disorder which followed.
"These are scenes we do not expect to see in our communities, particularly a close-knit community such as Ely.
"The level of violence towards emergency services and the damage to property and vehicles was totally unacceptable."
The riot was condemned by various politicians from across the political spectrum.
The Prime Minister’s official spokesman said: “The reports of disorder, violence, arson and specifically attacks on police officers are appalling and unacceptable.
"We remain grateful to the emergency services and first responders for all their support to the community and restoring order.”
Alun Michael, South Wales Police and Crime Commissioner, told BBC Radio 4’s Today programme: "It would appear that there were rumours, and those rumours became rife, of a police chase, which wasn’t the case.
"And I think it illustrates the speed with which rumours can run around with the activity that goes on on social media nowadays, and that events can get out of hand."
