Fiorentina captain Cristiano Biraghi was struck in the head in front of the West Ham end during the first-half of the final inside Prague’s Eden Arena by what appeared to be a plastic cup.
A stadium announcement warned supporters to stop their behaviour as a number of Hammers stars pleaded with their fans.
Biraghi required treatment after the object caused him to bleed from the back of his head and play was briefly halted.
The first half then resumed as normal before West Ham secured a dramatic win thanks to Jarrod Bowen’s winner in the closing stages of the game.
“West Ham United unreservedly condemn the behaviour of a small number of individuals who threw objects onto the pitch during tonight’s UEFA Europa Conference League final,” read a statement.
“These actions have no place in football, and do not in any way represent the values of our football club and the overwhelming majority of our supporters, who have behaved impeccably in Prague this week and throughout our last two seasons in European competition.
“We will work with the Police and other stakeholders to review the incidents and act against anyone found guilty of an offence. 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. There is no place for this kind of behaviour at West Ham United.”
