Poznan: As many as 500 Croatian fans shouted monkey chants at Italy striker Mario Balotelli and evidence has been passed to UEFA, according to the Football Against Racism in Europe (FARE) organisation.
A photographer reportedly saw a steward pick up a banana from near the field close to the Croatian section of the stand.
"FARE observers report between 300 and 500 supporters of Croatia involved in racially abusing Mario Balotelli at last night`s (Thursday`s) match in Poznan," FARE, which places anti-racism observers at Euro 2012 matches, wrote on Twitter.
"UEFA received the observers` reports this afternoon (Friday). We are working with them to provide as much information as possible."
"We congratulate the Italian fans for their support of Balotelli last night. Many sang his name to drown out the monkey chants."
UEFA has said it is investigating claims of racist abuse aimed at Balotelli by Spanish fans in Italy`s 1-1 draw with Spain Sunday, and by Russian fans at Czech player Theodor Gebre Selassie last week.