More than 50 police officers were injured and five men arrested after far-right riots in Southport, which broke out as the town reeled from a knife attack that killed three children. The Merseyside chief constable, Serena Kennedy, said the five were arrested in connection with riots in which 53 police officers were injured – 49 from Merseyside police and four from Lancashire. Three police dogs, Zoe, Ike and Quga, were also hurt. Kennedy said the rioters were there “purely for hooliganism and thuggery”. She estimated 200-300 people had been involved and said more rioters would be arrested. A 31-year-old man from St Helens; a 31-year-old man from West Derby, Liverpool; and a 39-year-old man from Southport were all arrested on suspicion of violent disorder. Jordan Davies, 32, from Southport, was charged with possession of an offensive weapon on Wednesday night. Merseyside police also announced the arrest of the fifth person, a 39-year-old man, following a report of a domestic incident in Southport after threats had been made to a male family member. The suspect was taken to hospital for treatment for a head injury, and officers recognised him from footage of the disorder on Tuesday, where he is alleged to have thrown rocks at officers. The suspect was also reported to have racially abused a patient while at the hospital. Special powers – known as section 60 and section 34 orders – are in place giving officers authority to stop and search individuals and direct people who are engaging in antisocial behaviour. As police dealt with the fallout of the riot, detectives were granted more time to question the 17-year-old boy held in connection with the atrocity in which three girls, aged six, seven and nine, were killed, and eight other children and two adults were injured. The boy, from the nearby village of Banks, was arrested on suspicion of murder and attempted murder after the horror unfolded at a Taylor Swift-themed children’s holiday club on Monday. Alice Dasilva Aguiar, nine, Bebe King, six, and Elsie Dot Stancombe, seven, were fatally stabbed, while five children and two adults remain in critical condition. Tuesday’s riot, near Southport mosque, marred a night of remembrance for the girls. The 53 police officers were seriously injured when bricks, stones and bottles were thrown and cars set alight after the vigil. Baseless rumours had been spread on social media misidentifying the suspect and falsely claiming he was an asylum seeker. He was born in Cardiff. On Wednesday, the metro mayor of Liverpool, Steve Rotheram, speaking in Southport, said: “What we saw last night was infiltration by people from all over the country, stirred up by social media and then whipped up into a frenzy whereby they were attacking the very people that everybody earlier in the day was celebrating for being the heroes, for running towards danger. It leaves a very sour taste in the mouth that these people believe they can come here and divide our community.” Jenni Stancombe, Elsie’s mother, intervened in a bid to cool tensions, writing on Facebook: “This is the only thing that I will write, but please, please stop the violence in Southport tonight. The police have been nothing but heroic these last 24 hours and they and we don’t need this.” After the violence, people rallied together to support the Muslim community and clear up the mess left by rioters. Dozens of residents were outside Southport mosque with brushes and shovels on Wednesday morning, and cleared bricks from a wall knocked down during the rioting. The mosque chair, Ibrahim Hussein, told the Guardian he had been “barricaded” inside the building with eight worshippers while hundreds of rioters descended on the mosque. He said: “It really was terrifying and it was uncalled for. There was no reason for it whatsoever. We just have to keep on going, there’s nothing else we can do.” Merseyside police said “a large group of people – believed to be supporters of the English Defence League [EDL]” – began to throw items such as bricks towards the mosque … at about 7.45pm”. The EDL is a far-right, Islamophobic group founded in 2009 by Tommy Robinson, whose real name is Stephen Yaxley-Lennon. Humza Yousaf, Scotland’s former first minister, called for the EDL to be banned under terror laws. Robinson insists the group no longer exists. The deputy prime minister, Angela Rayner, later said Yvette Cooper, the home secretary, would “be looking at” whether EDL should be proscribed under terrorism laws. The headline and text of this story were amended on 31 July to change the number of injured officers to 53