Keir Starmer has vowed to use the full force of the law against "far-right thuggery" after "marauding gangs intent on law-breaking" caused violence in UK towns and cities on Sunday.
In Rotherham, a group of 700 people surrounded a Holiday Inn Express hotel, where some lit a fire, smashed windows and managed to get inside the building where asylum seekers were staying.
Riot police also responded to violent scenes in Middlesbrough, Bolton, Hull and Weymouth, among other parts of the UK.
The prime minister vowed to do "whatever it takes to bring these thugs to justice" as he addressed the nation following ongoing unrest across the country, telling those involved they will "regret" taking part.
Sir Keir's address comes after a sixth day of escalating violence in response to the fatal stabbing of three young girls in Southport last week.
"People in this country have a right to be safe, and yet we've seen Muslim communities targeted, attacks on mosques," the prime minister said on Sunday.
"Other minority communities singled out, Nazi salutes in the street, attacks on the police, wanton violence alongside racist rhetoric, so no, I won't shy away from calling it what it is: far-right thuggery."
Since Saturday, 147 arrests have been made.
In Rotherham, at least ten police officers were injured with one left unconscious after anti-immigration demonstrators threw planks of wood at officers and sprayed them with fire extinguishers, South Yorkshire police said.
Some members of the group smashed windows to gain access to the Holiday Inn Express and a large bin was set alight.
The officer knocked unconscious suffered a head injury, the force said, adding that at least two others had suspected broken bones.
Hotel employees and residents, some of whom are asylum seekers, were "terrified", but no injuries were reported, police said.
One person has been arrested on suspicion of public order offences.
Home Secretary Yvette Cooper called the scenes "utterly appalling" and said police have government backing to take "the strongest action".
Meanwhile, a group of rioters in Middlesbrough smashed the windows of houses and cars and hurled objects at officers.
In Dorset, 600 people from opposing sides gathered on the seafront in Weymouth. Officers said there had been a "small number of low-level incidents", with one man arrested for a public order offence.
And in Bolton, anti-immigration protestors were confronted by a group of up to 300 masked people shouting "Allahu Akbar" - or "God is greatest".Greater Manchester Police issued a Section 60AA order in the town which requires people to "remove face coverings used to disguise or conceal their appearance". It will stay in force until 10pm on Sunday.
The violence follows similar scenes of unrest in Southport, Belfast, Hartlepool, Hull, Liverpool, Stoke-on-Trent, Nottingham, Sunderland and elsewhere earlier in the week.
In a statement on Sunday, the Home Office offered mosques greater protections as part of a new process, under which it said "rapid security" deployment can be requested in order to allow a return to worship as fast as possible.
Sir Keir indicated the response to the violence could mirror elements of how the 2011 riots were handled, at which time he was director of public prosecutions.
"We do have standing arrangements for law enforcement which means that we can get arrests... and convictions done very quickly," he said.
"I myself was part of that in 2011 when I was director of public prosecutions, and I'm determined we will do whatever it takes to bring these thugs to justice as quickly as possible."
Ministers have suggested that courts could sit 24 hours to fast-track prosecutions - as they did in 2011 - while police forces have measures in place to draft in extra officers to tackle potential unrest.
