Residents swept up broken bricks, shattered glass and burned plastic on Wednesday after protesters clashed with police outside a mosque in a northwest England town where three girls were fatally stabbed.

A violent crowd of several hundred hurled bricks and bottles at riot police and set garbage bins and vehicles on fire in Southport, hours after a peaceful vigil for the girls, aged six, seven and nine, who were killed during a Taylor Swift-themed summer holiday dance and yoga class. The ambulance service said it treated 39 police officers for injuries, 27 of whom were taken to hospitals.

U.K. 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 fuelled by anger and false online rumours about the 17-year-old suspect arrested on suspicion of murder and attempted murder.

 WATCH | U.K. police face violent crowd in Southport: 

U.K. police face violent crowd in Southport

Warning: This video, which shows violent clashes Tuesday in the English seaside town of Southport, includes explicit language. Police say the violence is believed to be linked to supporters of the English Defence League, which epouses far-right, Islamophobic views.

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.

Misinformation 'has real-world impact'

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.

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 a commonly used instrument in U.K. homicides.

About two dozen children, mostly girls, 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 children 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."

'I can't explain ... how horrific it is'

Witnesses described hearing screams and seeing children covered in blood in the mayhem outside the Hart Space, a community centre 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 U.K. subsequently banned the private ownership of almost all handguns.

Mass shootings and killings with firearms are exceptionally rare in Britain, where knives were used in about 40 per cent of homicides in the year to March 2023.