A police officer was seriously injured after thousands of Leeds United supporters celebrated in the street after the club claimed the Championship title.
Marcelo Bielsa's side secured promotion to the Premier League for the first time in 16 years on Friday and were crowned champions after Brentford lost at Stoke City on Saturday.
Around 7,000 people gathered in the city's Millennium Square where a number of fans hurled bottles at the police.
West Yorkshire Police said a female officer was struck in the head with a bottle and taken to hospital with serious head injuries.
The police also said other officers were injured during the celebrations and nine people were arrested.
"Throughout the weekend, fans have gathered across Leeds to celebrate the promotion of Leeds United into the Premier League," temporary assistant Chief Constable Oz Khan said.
"We have continued to impress upon fans the importance of the Covid-19 Government guidance and our approach has primarily remained as one of engagement and encouragement.
"On Sunday, almost 7,000 people gathered in Millennium Square in Leeds.
"Whilst the vast majority of fans were enjoying themselves and celebrating, there were a small minority of people who began to throw bottles at police officers."
Supporters also damaged parked cars outside of the club's stadium Elland Road on Friday during the promotion celebrations.
A Leeds fan started a GoFundMe page for the damage caused on Saturday and it has raised over £4,000 as of Monday morning.
Liverpool fans were also condemned by the club and police when supporters defied social distancing rules to celebrate the club's first league title in 30 years in June.