Large gatherings of Liverpool fans have been called "wholly unacceptable" in a joint statement by the club, police, council and a fans' group after crowds celebrated in the city for a second successive night.
Crowds gathered outside Anfield on Thursday as Liverpool secured their first league title in 30 years, after closest challengers Manchester City were beaten by Chelsea at Stamford Bridge. Merseyside Police made 10 arrests for public order offences on Thursday night during the celebrations.
Andy Cooke, chief constable of Merseyside Police, said on social media that 15 people were arrested on Friday night, and that officers were "subjected to a number of violent confrontations".
Detectives have charged a 26-year-old man with assault after a 32-year-old man from St Helens suffered serious head injuries during the mass gathering at the Pier Head in Liverpool City Centre on Friday night.
Craig Campbell, of Lemon Street, Kirkdale, will appear at Liverpool City Magistrates Court on Monday, June 29.
Officers have also charged a 19-year-old man with causing criminal damage following the Liver Building fire, which is believed to have caused at least £10,000 worth of damage.
Matthew Egglesden, of Turning Lane, Scarisbrick, has been remanded to appear at Liverpool Magistrates Court on Monday.
All persons arrested for the violent disorder have been bailed whilst investigations continue.
"[Friday] night, children and families were present alongside others and heavy-handed police intervention was therefore not appropriate at the time," Cooke said. "Later on in the night, 15 people were arrested for violent disorder and my officers were subjected to a number of violent confrontations. This is not acceptable.
"In relation to those who have been involved in criminal or anti-social behaviour in the city last night we will be looking at CCTV images and video from body-worn cameras to identify those responsible and we will take positive action."
Huge crowds of fans sang songs and let off flares outside Anfield, prompting the police to issue a dispersal order under the Anti-Social Behaviour Crime and Policing Act 2014 which will remain in place until Sunday.
A joint statement issued by Liverpool FC, Merseyside Police, Liverpool City Council and Spirit of Shankly read: "During the evening the over-exuberance of some of those in attendance, who were setting off flares and fireworks, resulted in a small fire on a balcony of the Liver Building which had to be put out by Merseyside Fire and Rescue Service.
"We cannot stress enough that behaviour such as this is wholly unacceptable and those who were setting off fireworks and flares in the crowd were putting the safety of those around them at risk.
"Clearly we are still in a public health crisis and we need to work together with the public of Merseyside to prevent the potential spread of COVID-19.
"The potential danger of a second peak still exists and we need to work together to make sure we don't undo everything we have achieved as a region during lockdown.
"The government has made it clear this week that if people continue to ignore guidelines around mass gatherings, whether they be at beaches or beauty spots, or for celebrations like we saw last night and the night before in Liverpool, then they have the ability to close down public spaces and will close areas if necessary.
"We all understand that fans want to celebrate, but now is not the time. We need to get through this first, and know that it is safe, before any victory parade can go ahead."
Mayor Joe Anderson took to to social media to reiterate that the spread of coronavirus was "still a real risk".
Mayor Anderson tweeted: "I appreciate #LFC fans want to celebrate but please, for your own safety, and that of others, go home and celebrate at home. Covid-19 is still a major risk and our city has already lost far too many people to the illness."
Metro Mayor Steve Rotheram also took to social media and said: "We're not saying this to be party poopers but hundreds of people have already died in our region because of coronavirus. Until it's safe for us to come together, please celebrate at home."
Liverpool City Council responded to the events stating: "We cannot move fans or take action to prevent them gathering. We do not have the power to do this.
"If you know someone out celebrating right now, please message them and ask them to bring the celebration home."
Mayor Anderson tweeted again on Saturday: "More in sorrow than anger, like most LFC fans and residents I condemn those that brought a negative focus on @LFC and our City. The pics showing peoples behaviour is being talked about instead of the fantastic achievement of LFC. Thank you to those fans that have listened."