The head of the British police contingent at Euro 2012 has urged Ukrainian officers to "make an example" of isolated racist incidents.
Assistant Chief Constable Andy Holt said there was "not much you can do" if large groups of supporters are involved in abusive chants and actions.
But he claimed the arrest of individuals could act as a deterrent to stop the problem becoming widespread.
At an open training session in Krakow, Poland on Wednesday, Dutch players were subjected to monkey chants with Holland captain Mark van Bommel branding the incident "a real disgrace".
A total of 18 British officers are deployed in Ukraine and six in Poland - led by the Association of Chief Police Officers - to help up to 8,000 local armed police deal with fans at games.
Around 3,000 England fans are expected to attend the team's opening match against France in the Ukrainian industrial city of Donetsk on Monday night.
The commander of the British officers will be in the police control room during the game to help the local force interpret the behaviour of England fans.
He admitted that the most difficult of England's three group fixtures from a police perspective will be the final game, when they face Ukraine.
England fans will be heavily outnumbered for the match in Donetsk on June 19.