LONDON — Residents swept shattered glass and cleared broken bricks and burnt plastic from streets Wednesday after far-right protesters clashed with police outside a mosque in a northwest England town where three girls were fatally stabbed earlier this week.

A violent crowd of several hundred hurled bricks and bottles at riot police, set garbage bins and vehicles on fire and looted a store in Southport, hours after a peaceful vigil on Tuesday for the girls, aged 6, 7 and 9, who were killed during a Taylor Swift-themed summer holiday dance and yoga class.

More than 50 officers were injured, with more than two dozen of those taken to hospitals, officials said.

“I am absolutely appalled and disgusted at the level of violence that was shown towards my officers,” Merseyside Chief Constable Serena Kennedy said. “Some of the first responders who attended that awful scene on Monday … then were faced with that level of violence.”

Four men were arrested, most on suspicion of violent disorder and one for possessing a knife and fighting. Kennedy said more arrests were expected.

Prime Minister Keir Starmer condemned the “thuggery” and said the protesters “hijacked” the community’s grief.

Norman Wallis, chief executive of the Southport Pleasureland amusement park, was one of dozens of people who turned up with brushes and shovels to clear the debris.

“It’s horrendous what those hooligans have done last night,” he said. “It was like a war scene. People from out of town just causing absolute mayhem.”

“But none of those people were the people of Southport,” he added. “The people of Southport are the ones here today cleaning the mess up.”

The protesters, who police said were supporters of the far-right English Defence League, were fueled by anger and false online rumors about the 17-year-old suspect arrested on suspicion of murder and attempted murder.

The suspect remained in custody on Wednesday and a magistrate gave detectives more time to question him before he is either charged with a crime or released without charge, police said. Police can hold a suspect for up to two days but can apply for an extension up to four days.

Police said a name of the suspect circulating on social media — spread by far-right activists and accounts of murky origin purporting to be news organizations — was incorrect and that he was born in Britain, contrary to online claims he was an asylum-seeker. The names of suspects under the age of 18 are usually not made public in Britain.

Patrick Hurley, the local lawmaker, said the violence by “beered-up thugs” was the result of “propaganda and lies” spread on social media.

“This misinformation doesn’t just exist on people’s internet browsers and on people’s phones. It has real world impact,” he said.

Chanaka Balasuryla, whose corner store was looted for booze and cigarettes, said he was horrified as he watched from home on a surveillance camera as a gang broke in. He was terrified because a woman and her daughter lived upstairs and he feared the looters would set the shop on fire.

He learned later that the woman had confronted the mob and told them the Windsor Mini Mart was her shop and asked them to stop.

He barely slept and got a call in the morning telling him to get down to his shop: people waiting to help him clean up and get back on his feet.

“It was terrifying last night,” he said. “But I feel safe again because people are here to protect us.”

The rampage in Southport, a seaside town near Liverpool, is the latest shocking attack in a country where a recent rise in knife crime has stoked anxieties and led to calls for the government to do more to clamp down on bladed weapons, which are by far the most commonly used instruments in U.K. homicides.

About two dozen children were attending a Taylor Swift-themed summer vacation workshop on Monday when a teen armed with a knife entered the studio and began a vicious attack, police said. Alice Dasilva Aguiar, 9, Elsie Dot Stancombe, 7, and Bebe King, 6, died from their injuries. Ten other people were injured, among whom five girls and two adults are in critical condition.

Swift wrote on Instagram that she was still taking in “the horror” of the event.

“These were just little kids at a dance class,” she wrote on Instagram. “I am at a complete loss for how to ever convey my sympathies to these families.”

Witnesses described hearing screams and seeing children covered in blood in the mayhem outside the Hart Space, a community center that hosts everything from pregnancy workshops to women’s boot camps.

Joel Verite, a window cleaner riding in a van on his lunch break, said his colleague slammed on the brakes and reversed to where a woman was hanging on the side of a car covered in blood.

“She just screamed at me: ‘He’s killing kids over there. He’s killing kids over there,’” Verite told Sky News.

“It was like a scene you’d see on a disaster film,” he said. “I can’t explain to you how horrific it is what I saw.”

Britain’s worst attack on children occurred in 1996, when 43-year-old Thomas Hamilton shot 16 kindergartners and their teacher dead in a school gymnasium in Dunblane, Scotland. The United Kingdom subsequently banned the private ownership of almost all handguns.

While knives have been used in about 40% of homicides each year, mass stabbings are unusual.