Uefa has confirmed racist incidents occurred at a Dutch Euro 2012 football training session in Poland, but said it has not yet received an official complaint from the team.
"Uefa has now been made aware that there were some isolated incidents of racist chanting that occurred at the open training sessions of the Dutch team in Krakow," it said in a statement.
The European governing body of the sport added: "Uefa has not yet received any formal complaint from the KNVB (Dutch football federation)."
According to Dutch players, abuse occurred during the open training session in Krakow , with captain Mark van Bommel branding it "a real disgrace".
The players were said to have been targeted by Polish fans as they began their practice session at the Stadion Miejski.
Van Bommel, who along with his team-mates visited Nazi German concentration camp Auschwitz on Wednesday, responded by leading the Dutch squad to the far side of the pitch, before hitting out at the perpetrators and vowing to take the matter to Uefa.
The PSV Eindhoven midfielder said: "It is a real disgrace, especially after getting back from Auschwitz, that you are confronted with this."
The England team is also based in Krakow and is due to visit Auschwitz I and Birkenau today, and on June 1 was given a talk by two Holocaust survivors .
Van Bommel added: "We will take it up with Uefa and if it happens at a match we will talk to the referee and ask him to take us off the field.
"You need to open your ears. If you did hear it, and don't want to hear it, that is even worse."
The Dutch side begins their Euro 2012 Group B campaign against Denmark on Saturday, and coach Bert van Marwijk was quoted as saying of the incident: "At least now we know what we can encounter here."
At a news conference on Friday, the Uefa chairman acknowledged the issue of racism but said both Poland and Ukraine had made significant advances in stamping it out.
Former Dutch skipper Ruud Gullit said: "Football is all about joy and about the two countries hosting it to get their name on the map.
"It is good that we are talking about this issue but it is sad that we have to talk about it."
Sky's Amanda Walker, reporting from Donetsk in Ukraine, said: "There is a sense of optimism about the tournament here, but it does seem it is already drowning in negative headlines about racism, not least this latest incident concerning the Dutch team.
"But Uefa said it is satisfied with the explanation that these fans were voicing their discontent that Krakow is not a host city."
England goalkeeper Joe Hart said the issue had been discussed within the team.
He said: "Our advice is just get on with it and see how Uefa and the referee deal with it - it is not for us to do."
The issue of racism has been a hot topic in the build-up to the tournament, and Uefa president Michel Platini confirmed referees can stop matches at this summer's tournament in Poland and Ukraine if a player is racially taunted.
But Mr Platini also warned any player who left the field unilaterally in protest over abuse from the stands would be yellow carded.
Italy and Manchester City striker Mario Balotelli had earlier said he intended to do exactly that if he found himself being racially abused.
Sky News has exposed extremists in Ukraine preparing for violence against visiting fans and chanting with Nazi salutes .
Former England centre-back Sol Campbell has advised fans to avoid the tournament and the families of black players Theo Walcott and Alex Oxlade-Chamberlain have declined to travel to watch the matches because of fears over racism.
Meanwhile, the British Government has announced it will boycott early Euro 2012 matches over human rights concerns - due to anger over the treatment of Ukraine's opposition leader Yulia Tymoshenko, who was jailed for seven years for "abuse of power while in office".