Prime Minister David Cameron was "appalled" by the ugly scenes at the end of the England Under-21s match against Serbia on Tuesday night, Downing Street has said.
The PM's official spokesman said the government was giving its full backing to a Football Association complaint over alleged racist comments by Serbian players, and sport minister Hugh Robertson had written to UEFA president Michel Platini urging an investigation.
Commenting on Mr Cameron's response, the spokesman said: "He was appalled by the scenes that we have seen in Serbia. We are determined to stamp out racism internationally and at home and we are giving our full backing to the FA's complaint on this issue."
The spokesman added: "Clearly it is for UEFA to investigate this issue but we would expect tough sanctions. If we are going to stamp out racism from football then it is no good giving derisory fines, as have been handed out in the past.
"It is not good enough to say that people should shake hands and forget about it."