By Emma Jane Kirby
BBC Europe correspondent in Brussels
European Commission President Romano Prodi has suspended a conference on racism after Jewish leaders accused the EU of fuelling anti-Semitism.
Some Jewish leaders say attacks are rising
The World and European Jewish Congresses said the EU had censored a study on rising attacks against Jews.
In a newspaper article, the groups also accused the EU executive of publishing a flawed poll about opinions of Israel.
Mr Prodi said he was "shocked" by the attacks and said progress at the forum was unlikely in such an atmosphere.
The opinion piece in the Financial Times accused the European Union of "intellectual dishonesty and moral treachery" in handling the issue of anti-Semitism.
Edgar Bronfman, the president of the World Jewish Congress, and Cobi Benatoff, the head of the European Jewish Congress, wrote the article in protest at the publication of what they called "a dangerously inflammatory" EU poll in which Israel was named as the biggest threat to world peace.
The Jewish leaders also accused the EU of censoring a study it had commissioned from its own racism watchdog which implicated Muslim minorities in anti-Semitic incidents.
Mr Prodi was quick to stress that fighting all forms of racism remained at the top of his agenda.
"This is a big problem. We must fight against anti-Semites," he said.
"This is one of the European dangers, and so we've taken it very seriously. We give the biggest priority to this terribly important, political, moral, and ethical issue."
Following the publication of the controversial poll last year, Mr Prodi decided to organise a conference on anti-Semitism.
But after hearing the accusations made by the Jewish leaders he called for the meeting to be suspended, warning little progress could be made in such a "bad atmosphere."