Police in Middlesbrough arrested 35 people during violent riots on Sunday.
Large crowds of far-right protesters clashed with police.
"The level of violence we have seen today is staggering," Assistant Chief Constable David Felton said. "We know the shocking scenes across Middlesbrough today will have caused alarm amongst communities."
Late in the day officials said most of the violent crowds had dispersed but officers remained in the area dealing with some disorder.
The riots resulted in significant damage to the Crown Court, the University and a number of properties in the Parliament Road area.
Cleveland Police also arrested 55 people linked to violent disorder in Teesside. In addition to the 35 arrests in Middlesbrough Sunday, the number of those arrested in connection with the disorder in Hartlepool last Wednesday now stands at 20.
England has been marred by violence since an attacker killed three young girls and injured several others in a mass stabbing at a Taylor Swift-themed dance event.
False reports that the crimes were committed by an immigrant stoked the initial protests.
Cleveland Police said there would be an increased police presence across towns and communities in the coming days due to calls on social media for more protests.
