LONDON (AP) — Several British police officers were injured in confrontations between far-right activists and anti-racism protesters on Saturday, following a stabbing rampage at a dance class earlier this week that left three girls dead and several injured.

With dozens of similar gatherings planned across the country this weekend, police have launched a massive security operation, sending thousands of extra officers onto the streets, many in riot gear. Police have also made more jail cells available and are deploying surveillance and facial recognition technology.

On Saturday, Merseyside Police said several officers had been injured in “serious disturbances” in central Liverpool, about 20 miles from the scene of the knife attack in the coastal town of Southport in northwest England.

In a series of posts on social media platform X, the police in charge of Liverpool and Southport said there was “no place for this despicable behaviour which disrupts the lives of citizens who live in the city or visit to enjoy the amenities the city has to offer.”

And Humberside Police said in a statement that three police officers were injured and four people were arrested following unrest in Hull, a city in northeast England. Earlier, windows were smashed at a Hull hotel used to house migrants.

Elsewhere, bricks were thrown at police in Stoke-on-Trent, central England, and scuffles were also reported in Belfast, Manchester and Nottingham.

There were no reports of far-right demonstrations in London. Regardless, thousands of pro-Palestinian demonstrators marched peacefully through the city to protest against Israel’s military operation in Gaza.

Britain’s new Labour Prime Minister Keir Starmer held an emergency meeting with ministers on Saturday, where he said the police had the government’s “full support” to take action against “extremists” who attack police officers and try to “sow hatred,” according to his office at 10 Downing Street.

The latest outbreaks of violence came a day after protesters in Sunderland, northern England, threw beer kegs and stones at police officers. A car and the building next to a police station were set on fire and 12 people were arrested.

The violence broke out earlier this week, reportedly in protest against Monday’s knife attack in Southport. A 17-year-old man was arrested.

False rumours that the young man was a Muslim and an immigrant spread online, fuelling the anger of far-right supporters. Suspects under the age of 18 are not usually named in Britain, but Judge Andrew Menary ordered the identification of Axel Rudakubana, who was born in Wales to Rwandan parents, in part to prevent the spread of misinformation.

In a press conference on Saturday following the clean-up in Sunderland, Northumbria Police Chief Mark Hall described Friday’s violence as “unforgivable” and said four police officers had been injured, three as a direct result of the unrest. He also said a horse rider had suffered serious injuries in an accident and was currently receiving treatment in hospital.

“Throughout the evening, our officers were confronted with serious and sustained violence,” he said. “Make no mistake: If you were involved in last night’s incident, you must expect to face the full force of the law.”

According to police, many of the actions are being organised online by shady far-right groups who are mobilising support online with slogans such as “Enough”, “Save our children” and “Stop the boats”. Counter-protests are also expected from the organisation Stand Up To Racism.

Since the knife attack, far-right protesters have held several violent gatherings. On Tuesday, they clashed with police outside a mosque in Southport – close to the scene of the gruesome stabbing – and the next day they threw beer cans, bottles and flares near the Prime Minister’s office in London. Many in Southport have expressed anger at the organised violence in the wake of the tragedy.

The attack on children during a Taylor Swift-themed summer dance class on Monday shocked a country where knife crime is a long-standing and vexed problem but mass stabbings are rare.

Rudakubana was charged with murder in connection with the attack that left 9-year-old Alice Dasilva Aguiar, 7-year-old Elsie Dot Stancombe and 6-year-old Bebe King dead. He was also charged with 10 counts of attempted murder of the eight injured children and two adults.

Starmer has blamed the violence on “far-right hatred” and vowed to put an end to the chaos. He said police across the UK would be given more resources to prevent “a breakdown of law and order on our streets”.

At a press conference on Thursday, the prime minister said the street violence was “clearly motivated by far-right hatred” and announced a program to enable police to better share information across agencies and make arrests more quickly.

“This is coordinated, this is deliberate,” Starmer said. “This is not a protest that has gotten out of control. It is a group of individuals who are absolutely bent on violence.”

Pan Pylas, The Associated Press