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:
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:
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."