The first joint initiative to combat Jewish support for the English Defence League within the community has been launched.
The "Not in our name - Jews against the EDL" campaign is backed by more than a dozen organisations, including the Board of Deputies, Community Security Trust, the Israeli Embassy, and Jews for Justice for Palestinians.
More than 500 people have already pledged their support.
But Roberta Moore, head of the EDL Jewish Division, claimed the campaigners had "betrayed the Jewish community" and challenged them to a filmed public debate. She said: "Let's have it all out in the open once and for all."
The initiative of the Union of Jewish Students, the campaign is a response to the creation of a "Jewish division" by the extreme right-wing anti-Islamic-fundamentalist group earlier this year, and the EDL's pro-Israel protest outside the Israeli Embassy last month, which was supported by American rabbi Nachum Shifren.
The "Not in our name" group's founding pledge states: "The Jewish community has always been at the forefront of anti-fascism. From Cable Street to defeating the BNP at the ballot box, we have been unafraid to speak out against those who seek to spread fear and hatred in our communities.
"Now our community faces a new threat. The EDL claims to be our allies in the fight against extremism. In reality, they are violent racists with BNP members and Nazi sympathisers among their ranks.
"It is time for the Jewish community to come together as one to expose the EDL as the racist thugs they are."
UJS campaigns director Carly McKenzie said: "We felt this was a prime opportunity to bring the whole community together with one loud voice."
Edie Friedman, director of the Jewish Council for Racial Equality, which is backing the initiative, said: "It's terribly important for different sections of the community, as well as individuals, to stand up and say categorically, 'not in our name'. It's unbelievable that such an organisation can appropriate Jewish support."
Karen Pollock, chief executive of the Holocaust Educational Trust, said: "At the HET we educate about the dangers of racism and discrimination and it is vital that we stand up against groups such as the EDL who preach hatred and division in our communities."
Ms Moore responded: "We are not bothered by their futile threats and attempts to silence us. We, and much of the Jewish community, know they lack the courage to address the issues we highlight. They have not been doing their job for a long time, and seem to have not only abandoned but betrayed the Jewish community in general."