Czech police have detained several people following a clash between West Ham and Fiorentina fans ahead of the Europa Conference League final in Prague on Wednesday.
Fans of the Italian side are said to have approached West Ham fans with “chains and belt buckles”.
A 17-year-old witness said: “They were throwing flares and firecrackers.”
He added: “They had chains and belt buckles and everything. They come here, try giving it, and then they ran down the road.”
The force said Italian fans attacked West Ham fans in a bar in the country’s capital, with three people being left injured as a result.
It was also confirmed a police officer had been attacked during the incident.
Following the clash, 16 people were detained as police “restricted the personal freedom” of those suspected to be involved.
Outside the Tek’ila Tek’ila bar in the city centre, a burnt-out chair and broken glass were seen littered across the ground.
One West Ham fan, who did not want to be named, said “a large group” of Italian fans attacked the bar.
“About eight Italians walked past, swinging bands and chains,” he said.
He added: “Five minutes later there was a big group that come down the road and attacked us.”
The man said five West Ham fans were injured.
He said: “Three of our mates (were injured), out of all of this lot there were five. Three of them were our mates. They’ve gone to hospital.”
He added that one of his friends was “quite badly” injured with a “massive cut” on his head.
Videos were also shared on social media appearing to show people throwing chairs at each other in Prague on Wednesday.