"We believe this to be an isolated incident, and we are not currently looking for anyone else in relation to it," Merseyside Police Assistant Chief Constable Jenny Sims told a press conference, adding a 53-year-old white British man had been arrested.

"The incident is not being treated as terrorism," she added.

Some 27 football fans were hospitalised, including two who were seriously injured, after a dark-coloured vehicle swerved through the huge crowds hitting people in its path, minutes after the players' open-topped bus passed by.

Four children were among those hurt, including one seriously.

Tens of thousands of people had turned out in torrential rain for what should have been jubilant celebrations to see the northwest English side's victory parade.

The bus carrying the team had passed by Water Street just minutes before the car ran into the crowd, witnesses said.

"It was extremely fast," said Harry Rashid, 48, from Solihull, near Birmingham, central England, who was at the parade with his wife and two young daughters.

"Initially we just heard the pop, pop, pop of people just being knocked off the bonnet of the car," he told reporters.

"It was horrible and you could hear the bumps as he was going over the people."

Witness Mike Maddra said the "car turned left, mounted pavement, come towards us and runs towards the buildings."

He said "we got out the way and it was speeding up".

- 'Remarkable bravery' -

Twenty other people were treated at the scene for their injuries, in a large blue tent set up on the street.

Four people, including a child, were trapped under the car and had to be removed, said Nick Searle, Merseyside Fire and Rescue Service chief fire officer.

Prime Minister Keir Starmer commended the "remarkable bravery shown by the police and other emergency services".

"They are supporting and caring for those injured in these terrible events," he said in a statement, adding: "the whole country stands with Liverpool".

BBC reporter Matt Cole who was at the parade with his family described hearing "screams ahead of us and suddenly this dark blue car just came through the crowd.

"It just wasn't stopping. I managed to grab my daughter who was with me and jump out of the way," he said.

Images shared on social media showed the car being brought to a halt and swarmed by angry fans, who broke the back windows as police sought to hold them back.

Liverpool had earlier been a sea of red as hundreds of thousands of supporters packed the city's streets to celebrate winning the Premier League title with Arne Slot's successful squad.

Star players Mohamed Salah and Virgil van Dijk led the festivities on the top deck of the bus.

- 'Difficult day' -

Plumes of red smoke from flares had filled the air as the players took four hours to cover the 10-mile (16-kilometre) route.

Liverpool FC said on X they were working with Merseyside police, adding: "Our thoughts and prayers are with those who have been affected by this serious incident".

And Liverpool metro mayor, Steve Rotheram, said it was "a difficult day for our city region, but we stand together".

Everton, Liverpool's Merseyside rivals, also said the club's "thoughts are with all those who have been affected by this serious incident in our city".

Liverpool's record-equalling 20th English top-flight title was secured nearly a month ago as Slot's men wrapped up the Premier League with four games to spare.

However, they were only presented with the trophy after Sunday's final match against Crystal Palace.

Despite Liverpool's storied history, the club's fanbase had been waiting 35 years to collectively celebrate a league title.