“Racist thuggery has no place on our streets. Anyone attacking the police will be met with full force of the law,” Johnson tweeted on Saturday.

The prime minister followed that by saying current protests over police brutality and racial inequality “breach current guidelines.”

“These marches & protests have been subverted by violence and breach current guidelines. Racism has no part in the UK and we must work together to make that a reality.”

Video from London showed Black Lives Matter activists clashing with counter-protesters on Saturday, as well as police officers at the scene. Smoke bombs and bottles were thrown at police, something that has occurred at these protests in the past. Reporters trying to cover the scuffles were also met with violence.

Johnson has been critical of the protests, previously tweeting on Friday that the demonstrations have been “hijacked by extremists” and people should stay clear of any gatherings that violate the country’s lockdown measures meant to stop the spread of Covid-19.

“It is clear that the protests have been sadly hijacked by extremists intent on violence. The attacks on the police and indiscriminate acts of violence which we have witnessed over the last week are intolerable and they are abhorrent,” Johnson tweeted.

“The only responsible course of action is to stay away from these protests,” he added.