West Ham condemned the behaviour of “a small number of fans” after Fiorentina’s Cristiano Biraghi was hit by an object thrown from the stands at the Europa Conference League final.
Biraghi was left bloodied after cups and other items were thrown as he took a corner during the match in Prague.
West Ham said “these actions have no place in football”.
It followed trouble before the game, as 16 people were arrested after an incident at a bar.
Czech police said Italian fans attacked West Ham supporters in a bar, leaving three people injured.
West Ham said the fans’ actions inside the Fortuna Arena “do not in any way represent the values of our football club and the overwhelming majority of our supporters”.
The club added that fans had “behaved impeccably” in Prague and during their time in European competitions in the last two seasons, and that they would assist police in finding the culprits.
“In line with our zero-tolerance approach, anyone identified will have their details passed to the police and will be given an indefinite ban and therefore be unable to enter London Stadium and travel with the club,” a statement said.
As Biraghi received treatment for his head injury in the first half, a PA announcement urged supporters to stop throwing objects onto the pitch and to “please respect players and the officials”.
Fiorentina coach Vincenzo Italiano said Biraghi “has big gash in the back of his neck and stitches”.
West Ham ended their 43-year wait for a major trophy as Jarrod Bowen scored a last-minute goal to beat Fiorentina.
Fiorentina fans were ‘swinging bands and chains’
Earlier on, Hammers fans were attacked by the Italian side’s supporters at the Tek-ila Tek-ila bar in Rytirska Street in the city centre.
Three people were injured, with police confirming an officer had also been attacked during the incident.
One West Ham fan, who did not want to be named, told PA News his friend was “quite badly” hurt with a “massive cut” on his head.
Prague emergency service spokeswoman Jana Postova told AFP two people were treated at the scene and one was transported to hospital with a light head injury,
The fan added: “About eight Italians walked past, swinging bands and chains. Five minutes later, there was a big group that come down the road and attacked us.”
A 17-year-old witness, speaking to PA News, said West Ham fans had “done nothing wrong” and Fiorentina supporters “were throwing flares and firecrackers”.
