A clean-up operation is under way after a night of violence during which four police officers were injured and 10 people arrested.
Beer cans and bricks were thrown at riot police outside a mosque in Sunderland and a Citizens Advice office was torched.
North East Mayor Kim McGuinness said she was appalled by the “thuggery” and attacks on police.
Friday’s chaotic evening was the latest outbreak of rioting across England following the killing of three young girls in Southport on Monday.
As violence spread around Sunderland on Friday, mounted police pushed back demonstrators, some of whom were wearing masks.
The window of Sunderland Central Police Office was smashed in and the neighbouring Citizens Advice branch, on Waterloo Place in the city centre, was set on fire.
Locals said the air was still filled with smoke on Saturday morning.
Rioters also confronted police near a mosque on St Mark’s Road, a mile from where the fire was set.
Northumbria Police said two of the officers injured by crowds throwing beer cans and bricks were still in hospital.
Asked on BBC Breakfast whether there was any prior knowledge of events or protests planned for Sunderland, Ms McGuinness said: “We saw that these far-right groups were advertising what they called a peaceful protest yesterday in Sunderland.
“That was anything but peaceful.
“It was out and out crime and violence and the police response was strong, protecting a mosque and really having to stand up to very sustained crime and violence from these thugs.”
Posting on X, Sunderland City Council said: “We are appalled by the events that have unfolded.
“Sunderland is known for being a warm and friendly place, the events of tonight are not a reflection of this proud city and its people.
“We will come together, as we always do, to restore calm for our communities.”
The mayor added: “Things like this really affect the way that local people feel, but the clean-up overnight from Sunderland Council has clearly been absolutely massive.
“And what I’m really heartened by, alongside the thousands of people contacting me saying ‘this is not what we’re about, we’re about that love and that compassion’, is the fact that people in Sunderland are going to come together this morning and help with that clean up.
“And I think that really shows the true spirit of what we are as the North East and as Sunderland.”
Home Secretary Yvette Cooper said those stoking disorder in towns and cities “do not represent Britain”.
She gave full backing to police “to take the strongest possible action”.
Meanwhile, in Liverpool on Friday a small scuffle broke out between protesters and people protecting the Abdullah Quilliam Mosque.
Those outside the mosque chanted: “Say it loud, say it clear: Refugees are welcome here.”
Irene Tomkinson, 75, from Southwick and Mavis Stamp, 64, of Pennywell, joined the clean-up operation.
Ms Tomkinson said: “I feel incredibly emotional this morning to be here and show we’re grafters and we’ve put two fingers up at the rioters.”
Ms Stamp added: “This is our city and they won’t win.”
Yusuf Meah, 41, Imam at the University of Sunderland said the community was determined to come together in unity in the aftermath of the riot.
“Last night doesn’t represent the city, we’ve got to come together as a community and show unity, ” he said.
Graham Boyle, 63, Houghton-le-Spring added: “What happened last night showed up our city.
“Seeing people here working together this morning overshadows anything that happened last night.”
Samuil Hussain, 24, who also joined other volunteers, said: “I think it’s beautiful, these are the real people that represent Sunderland.”