Police in Britain initially reported that 20 police officers were assaulted or injured in confrontations with protesters Sunday night. On March 25, police revised the injury assessment, saying that no officers suffered broken bones or a punctured lung, as originally claimed. According to police, 40 officers were injured in total. This article has been updated to reflect the new information.

LONDON — At least 20 police officers were left with broken bones and other serious injuries after a protest in Bristol, England, turned violent Sunday night, with thousands gathering to denounce a bill designed to give authorities broader powers to clamp down on peaceful protests, police said Monday. Later in the week, police changed their account, saying 40 officers were injured but that no broken bones or a punctured lung could be confirmed.

The Police, Crime, Sentencing and Courts Bill, which is making its way though Parliament, outlines broad measures, including changes to rules governing protests. Under the legislation, authorities would be able to impose start and finish times and set noise thresholds, with fines of up to $3,400 for noncompliance.

Critics of the bill say the move is authoritarian and an attack on democratic rights.

Home Secretary Priti Patel called the scenes in Bristol — about two hours from London — “thuggery and disorder by a minority.”

The bill also would protect statues, with those found guilty of damaging monuments potentially liable to be sentenced to up to 10 years in prison.

Police said Monday that seven arrests were made in the Bristol protest. Prime Minister Boris Johnson, speaking on Sky News, called the chaotic scenes that continued long into the early hours of Monday morning “unacceptable.”

England is set to lift a ban on protests, a measure meant to slow the spread of the coronavirus, on March 29. Demonstrators have accused police of heavy-handed enforcement of the ban, especially after the arrest of mourners at a vigil for Sarah Everard, who disappeared earlier this month and whose body was found a week later. A police officer has been charged with kidnapping and murder in the case.

Although the Bristol event began peacefully, with masked protesters carrying signs that read, “We deserve a voice” and “Freedom to protest is fundamental to democracy,” the gathering turned violent as night fell, with some demonstrators hurling stones at police, setting vehicles on fire and vandalizing a police station, trapping officers inside.

The words “kill the bill” were etched onto roads as smoke from burning police vehicles billowed into the skies. At least two people defecated at the feet of officers, officials said Monday.

Andy Marsh, chief constable of Avon and Somerset, expressed concern Monday that the scenes may be repeated across other cities as the government continues to try to expand police powers.

Among those who have expressed concerns over the new bill are opposition Labour lawmakers and conservative former prime minister Theresa May, who said last week that “freedom of speech is an important right.”

Along with some wary politicians, 700 of Britain’s leading academics signed a letter published by the Independent that slammed the measure as “an existential attack on the right to protest.”

Bristol Mayor Marvin Rees told BBC Radio that the protest could prove counterproductive, with the “lawlessness on show” Sunday likely to be “used as evidence” to “promote the need for the bill.”

Rees branded the people attacking officers and destroying police vans “thuggish citizens,” saying that some had hijacked the protest to live out “their revolutionary fantasies.”

Rees said he hoped locals would work with officials, who have released CCTV footage, to help identify those involved in the riots.

Sue Mountstevens, Avon and Somerset’s police and crime commissioner, said the behavior at the protest showed “reckless disregard” for people’s lives and the safety of officers.

Many expressed concern that officers lost control of the situation — despite the use of riot shields, batons and dogs — and likened the scenes to those from riots in 2011, in which Tottenham, an area in north London, and other places across the country were torched, looted and vandalized following the death of Mark Duggan, a 29-year-old Black man, at the hands of a police officer.

Photos shared to social media Monday morning showed a large cleanup in the Bristol town center.