A 13-year-old boy is among four people arrested after two police officers were injured in what the home secretary described as a “disgusting, violent attack”.
Footage of the assault in Hackney, east London, on Wednesday afternoon, has been widely circulated on social media.
Detectives said they are confident there are no further suspects after the incident in which a member of the public flagged down the two officers in the Frampton Park Road area at about 3.30pm.
They told the officers they had just been assaulted and directed them towards the alleged suspect.
As an officer attempted to speak to those apparently involved, one of the men resisted and a struggled took place.
A number of other people became involved while the officer was on the ground.
The two officers, one male, one female, suffered minor injuries but did not require hospital treatment.
Video showed an officer pinned down on the ground and being kicked, while his female colleague was pushed as she tried to intervene.
Several men surrounded the officers, swearing, shouting and filming on their phones, with one even dancing and taking a selfie during the assault.
Other officers who came to the scene arrested two men, aged 32 and 20, on suspicion of assaulting an emergency worker and they were taken to an east London police station.
That evening a 13-year-old boy was arrested, and on Thursday, a 34-year-old man was also arrested.
On seeing the video, Home Secretary Priti Patel tweeted: “Sickening, shocking & disgraceful.
“My thoughts are with the outstanding @metpoliceuk officers who were subject to this disgusting violent attack.”
After hearing from Sky News that four people had been arrested, mayor of London Sadiq Khan tweeted that “this kind of behaviour is completely unacceptable and simply will not be tolerated”.
Central East BCU Commander Marcus Barnet said: “Thousands of people, including myself and the officer’s colleagues, have seen the video of this incident circulating on social media and have been horrified by what happened.
“My officers were in the process of making an arrest when they were attacked. They have suffered cuts and bruises and thank goodness they were not seriously injured.
“They have been back out at work today, which is testament to their dedication. We have ensured the welfare of the officers and they continue to be supported by their colleagues.
“An investigation into the incident is ongoing and a number of arrests have been made.
“Police officers do not come to work to be attacked. I have been an officer for 27 years and incidents such as this still shock me.
“It is never OK. We are engaging with our community partners to discuss what happened and I hope that anyone who witnessed what happened comes forward and speaks with us.”
Anyone with information is asked to call police via 101 quoting reference Cad 4315/10Jun or Crimestoppers anonymously on 0800 555 111.