The leader of the English Defence League's Jewish Division has quit, claiming the organisation has been infiltrated by "Nazi elements".
Activist Roberta Moore, who has led the division since its launch last year, has been a divisive figure within the EDL.
The JC reported on rifts within the anti-Islamic fundamentalism group last month, apparently caused by attempts to link to organisations such as the far-right American Jewish Task Force and what one EDL spokesman said was Ms Moore's "gung-ho attitude".
She has repeatedly denied holding extremist views and has claimed opponents have lied about her actions to "destroy the group".
On the Jewish Division's Facebook profile, Ms Moore claimed "Nazi elements" had hijacked the EDL. She wrote: "I do wish the EDL the best of luck in this fight, as they surely need it. And I sincerely hope that the leaders will get the strength to squash the Nazis within, for they will destroy this movement if allowed to remain, and thus lose the fight against the Islamisation of their countries."
Ms Moore's departure has led to American blogger and commentator Pamela Geller also withdrawing her support for the EDL.
Ms Geller, co-founder of the Stop Islamisation of America group and an ally of Ms Moore, opposed plans to build an Islamic cultural centre near Ground Zero in New York.
On her blog, Ms Geller said: "It has become increasingly clear that the EDL has morphed and diverged from its original course. They now have clearly been infiltrated by the worst kind of influences. They are now unrecognisable to me."
EDL leader Tommy Robinson said the Jewish division had been built on "Israel's right to defend itself" and added: "The EDL will not be deterred from its support for Israel and the Jewish people. Recently there have been internal arguments, which are nothing more than that.
"Every large family has its disagreements, but, when push comes to shove, we all stand on the same side.
"Some people have jumped on the EDL bandwagon and tried to use our platform to express antisemitic views. These statements are not in accord with the fundamental beliefs of the EDL. These people are not welcome, never have been welcome, and never will be welcome within the EDL.
"We reject all antisemitism."
He said the EDL wanted "Jewish people and all free people to remain free forever. We all stand together in this fight against Islamic jihad".
The Board of Deputies, CST and other communal groups have repeatedly warned British Jews against supporting the EDL.