Five officers have been injured and 10 people arrested during clashes with anti-vaccine protesters in central London, the Metropolitan Police has said.
The force said a number of protesters had “become violent” towards police during action in the capital.
In a tweet, Scotland Yard said “These ugly scenes are not why police officers come into work. This level of violence is totally unacceptable and it will not be tolerated.
“Five officers were injured while policing a protest group in Canary Wharf and at South Kensington.
“Crowds quickly became hostile when they reached a building in Canary Wharf. Officers moved in to prevent those protesting from gaining entry.”
The force said crowds had continued to clash with police after moving to South Kensington, adding: “Throughout the day, our officers worked hard to de-escalate any conflict.”
The force said: “Ten people were arrested during the course of this police operation. Those suspects are in police custody.”
Earlier on Friday, a group of anti-vaccine protesters tried to storm the headquarters of the Medicines and Healthcare products Regulatory Agency (MHRA) in central London.
Footage posted on social media shows a group of demonstrators being held back by police as they try to get into the building on Cabot Square in Canary Wharf on Friday afternoon.
Crowds were later seen leaving the area towards the Underground station.
The MHRA is the Government body responsible for approving the coronavirus vaccines.
The Metropolitan Police said officers attended a demonstration outside a commercial building on Cabot Square in Canary Wharf and guarded the entrance to the building.
Andrew Wood, councillor for Canary Wharf, said leaflets were being handed out about the vaccination of children.
He added: “The police have been here all week because we were expecting Extinction Rebellion, so most of the police and security’s been outside the banks.
“So whether the anti-vaxxers realised this or not the police were ready for a protest, it’s just that it was anti-vaxxers not Extinction Rebellion who turned up this afternoon.”
The protest comes after journalists working for ITN were trapped in their offices when a group of anti-vaccine and anti-lockdown protesters forced their way into the broadcaster’s London headquarters on August 23.
That followed an incident on August 9 when a crowd thought to be made up of anti-vaccine protesters tried to gain access to the BBC’s old headquarters in White City, west London.