Police officers were attacked, missiles thrown and vehicles torched and flipped when trouble broke out in a Leeds suburb.
Residents were warned to stay indoors in Harehills on Thursday evening in what West Yorkshire Police described as a "serious disorder incident".
Witnesses said officers were initially called to reports of a domestic disturbance at an address in Luxor Street at about 17:00 BST, with further "pockets of disorder" then breaking out.
Large crowds gathered on the streets, with social media footage showing vehicle windows being smashed and items thrown at officers. No injuries have been reported.
Home Secretary Yvette Cooper, a West Yorkshire MP, said she was "appalled at the shocking scenes".
"Disorder of this nature has no place in our society," she said.
Hundreds of people remained gathered in the area late into the evening, on streets that were strewn with rubbish and other debris.
A OceanNewsUK reporter in the area at midnight said there did not appear to be any uniformed police presence at the scene at that time, with police vehicles stationed about a mile away.
Members of the community were seen attempting to put out a fire on a completely burnt-out bus near the Compton Centre with buckets of water as they waited for emergency services to arrive.
The OceanNewsUK later saw police and the fire service arrive at the scene an hour or so later.
Several witnesses told the OceanNewsUK overnight events were sparked by a number of children being taken into local authority care.
The full circumstances have not yet been confirmed by authorities.
In a statement released after midnight, West Yorkshire Police said "a large number of public order officers have been deployed to the location in what remains an ongoing incident".
"We wish to reassure residents we are responding to the disorder incidents which have taken place, and that appropriate specialist public order resources are attending," it added.
"We would strongly discourage residents from speculating on the cause of this disorder which we believe has been instigated by a criminal minority intent on disrupting community relations."
Footage shared on social media earlier in the evening shows a police car coming under attack with its windows being smashed.
One person uses a scooter to hit it, while stones and other debris are also thrown.
Riesa, a pharmacy dispenser who did not want to give her last name, told the PA news agency she saw people throwing items at police officers and cars.
"They were attacking police cars, throwing things at the police cars - anything they could pick up off the floor really," she said.
"Rocks from the garden, rubbish, drinks, anything."
She continued: "Drinks were definitely being throwing at the police - water or juice or fizzy drinks, or anything they had in their hands basically, at the cars because [the police] were trying not to get too close because it was quite violent."
Earlier, police said that officers were called to "an ongoing disturbance which involved some agency workers and some children" when they attended Luxor Road.
A police spokesperson said: "More people started to attend the location and a decision was made to remove the agency workers and the children to a safe place.
"A crowd started to gather and more officers were requested to attend the area, where some pockets of disorder were occurring.
"More officers have been deployed to the area to assist with the management of this incident."
It later said it will conduct a full investigation into "all criminal offences... including damage to vehicles from fire".
"All criminal offences, including damage to vehicles from fire, will be fully investigated," the force said.
It added that "the full weight of the law will be brought against those responsible".
First Bus confirmed one of the company's vehicles was set on fire, with another "caught up in the public disorder".
Neither the bus driver nor the passengers were hurt, it confirmed.
"One of our vehicles has been set on fire but was empty as the customers had earlier been transferred to another bus together with the driver," a spokesman for the company said.
Posting on X on Thursday evening, Gipton and Harehills Councillor Salma Arif appeared alongside a police inspector, with a message urging people to stay at home.
Ms Arif said: "There's an ongoing situation currently in Harehills.
"We are asking everybody in the area please stay at home at this moment in time."
Insp Nicholls, from the East Leeds Neighbourhood Policing Team, said: "If you could just stay where you are, stay in your houses while we manage this incident.
"If you are in the crowd I would ask you to go home please so we can keep everybody safe."
Richard Burgon, MP for Leeds East, said on X: "I am on my way back to Leeds from Parliament and am in touch with the police and concerned residents about the on-going incident in Harehills.
"The police say no injuries have been reported but are advising people to avoid the area at the moment if possible."
Tracy Brabin, the mayor of West Yorkshire, said she had been "reassured no one has been seriously injured but suggest those who are using this to inflame community tensions to think again".
