UEFA has said that it has been informed of "isolated incidents" of racist chanting at the Netherlands training session on Wednesday and warned that it will take action if it happens again.
The Dutch captain said they were subjected to monkey chants while training in the Polish city of Krakow.
Video of the training session, with monkey calls audible from the crowd has been released:
– Uefa statement on reports of racist abuse during a Dutch training session
UEFA has now been made aware that there were some isolated incidents of racist chanting that occurred at the open training session of the Dutch team yesterday in Krakow. UEFA has not yet received any formal complaint from the KNVB [the Dutch FA].
Should such behaviour happen at further training sessions, UEFA would evaluate the operational measures to be taken to protect the players.
UEFA has a zero tolerance policy when it comes to discriminatory behaviour and has given the power to referees to stop matches in case of any repeated racist behaviour.
The Dutch FA has told ITV News it has no plans to issue a formal complaint over the abuse.
A spokeswoman said that none of the players or coaches heard any racist abuse, although a few players moved to the other side of the pitch because it was too noisy.
She added that no-one has since made a complaint.
Asked whether the Dutch FA would reconsider in light of the new video, she replied "I don't think so."
The news of the racists calling has already sparked an outcry from other black players:
Tell me I didn't see this..the dutch team getting abuse already? The tournament needs to start asap&hope this isn't a sign of things to come
Jimmy Floyd Hasselbaink, Nottingham Forest first team coach and former Dutch striker has said it is:
"Not a surprise that racism has happened. UEFA allowing tournaments in these countries shows dealing with racism is not high on their agenda."