Uefa is investigating reports a banana was thrown on to the pitch during the Euro 2012 Group C match between Italy and Croatia on Thursday.A photographer reportedly saw a steward retrieving a banana and heard monkey chants directed at Italy striker Mario Balotelli.A Uefa spokesperson said: "We are looking into the reports."Alleged racist chanting in the Spain-Italy and Russia-Czech Republic games are already subject to investigations.A Spanish fans' group has said some of its country's supporters abused Balotelli in their game with Italy, while Czech Republic defender Theodor Gebre Selassie told reporters he "noticed" racist chants directed at him.Balotelli, who started the 1-1 draw against Croatia, said before Euro 2012 that he would "not accept racism at all" and would walk off the pitch if racially abused by fans.Netherlands players said they heard racist chanting during a pre-tournament open training session in Krakow.