Violence at a third night of protests in Bristol has been condemned as "disgraceful" by Prime Minister Boris Johnson.
Ten people were arrested after a Kill the Bill protest ended in scuffles.
Police said a "minority" of protesters "showed hostility" and arrests were made after a sit-down protest in front of a police station.
One journalist claimed he was assaulted by police during the operation to clear the streets.
Mr Johnson said a "mob" was "intent on violence" after "bricks, bottles and fireworks" were thrown.
Mass gatherings are currently banned under coronavirus legislation and anyone breaching regulations could be fined.
Protesters said they were unhappy about an element of the Police and Crime Bill, which would ban residing on any private or public land in vehicles without permission where they are causing "significant disruption, distress or harm to local communities".
Police assaulted me at the Bristol protest even though I told them I was from the press. I was respectfully observing what was happening and posed no threat to any of the officers. I have muted the latter part of the video to spare you all the pain of hearing my shrill voice. pic.twitter.com/a7a0Nnw0bG— Matthew Dresch (@MatthewDresch) March 27, 2021
Daily Mirror journalist Matthew Dresch posted a Tweet which he said showed him being assaulted by officers as they cleared the city centre, despite telling them he was a member of the media.
In response, the force said it was trying to contact Mr Dresch and that a free press was "a cornerstone of our democracy".
One Labour MP has called for an independent investigation into the policing of the most recent protest, after reports of journalists and marchers being injured.
Nadia Whittome, who represents Nottingham East, tweeted that the case for an investigation "was clear".
Last night saw disgraceful attacks against police officers in Bristol.— Boris Johnson (@BorisJohnson) March 27, 2021
Our officers should not have to face having bricks, bottles and fireworks being thrown at them by a mob intent on violence and causing damage to property.
The police and the city have my full support.
Home Secretary Priti Patel criticised the disorder and the "violence being directed towards the police".
"I'm in no doubt the silent, law-abiding majority will be appalled by the actions of this criminal minority," she said.
"Despite repeated warnings to disperse, it's clear these thugs were only intent on causing trouble.
"I am receiving regular updates and the police have my full support."
I am disgusted by the disorder in Bristol and the violence being directed towards the police.— Priti Patel (@pritipatel) March 27, 2021
I’m in no doubt the silent, law-abiding majority will be appalled by the actions of this criminal minority.
The protest had started earlier in the day on College Green before moving during the evening to Bridewell police station, the scene of disorder on Sunday.
Police in riot gear blocked access to the road and protesters sat in front of them in response.
But officers moved in after 22:00 GMT after the "atmosphere changed" and "people became physical".
Footage showed police in riot gear using shields to push protesters back.
Supt Mark Runacres, from Avon and Somerset Police, said "reasonable force had to be used".
"This is not something we ever want to do but we have a duty to uphold the law, prevent crime, and protect people and property."
He said many of the marchers had heeded police warnings to go home, something he was grateful for, but that some who stayed in the centre had attacked officers by throwing missiles including bottles, a bicycle pedal and eggs.
Supt Runacres added "at least three" of the people detained during the latest protest had been arrested for offences committed during Sunday's disorder.
He added the force was "concerned" there could be more protests in the city in the coming days, and that "it is something we are preparing for".
One protester, who did not want to be named, told the BBC she had decided to attend as the third reading of the new bill was on Monday.
"I think the government have deliberately put this bill for a time when people can't protest and I think that's really wrong," she said.
"That's why I came. To show my support for the protest."
Another protester said he appreciated the seriousness of the pandemic, but the long-term impact of the bill was too important to ignore.
"What you need to consider is that this bill will last for decades if it does pass, and that will have very serious consequences over Covid currently."
Independent journalist Martin Booth, who has been covering news in Bristol for the past decade, said: "At the start, some protesters placed daffodils in the lapels of police in the front line.
"The mood early on was calm, convivial even, as police wearing caps rather than helmets were happy to talk to protesters - a marked contrast to the previous Sunday and Tuesday."
He said at 22:00 GMT he saw more riot police and dogs arrive.
Mr Booth said he then saw a line of police "move as one" toward the protesters, many of whom were still seated on the street.
"This is when I first saw protesters swinging their arms at police, who were using their shields both for defence and attack," he added.
Bristol's Labour mayor Marvin Rees said the violence was "unwelcome" and that some protesters had damaged their cause by confronting the police.
"The question those engaging in the action should be asking is: is what I am doing advancing the cause I claim to be campaigning for?" he said.
"Many people protested peacefully but there are a number who refuse to go home and others who are here merely to cause conflict: the bill itself is not their cause, it is their opportunity.
"If the protests are meant to reduce the likelihood of the bill, then the actions of some of these protestors are politically illiterate and strategically inept."