The Private Eye article quoted Mr. Assange as saying the conspiracy was led by The Guardian and included the newspaper’s editor, Alan Rusbridger, and investigations editor, David Leigh, as well as John Kampfner, a prominent London journalist who recently reviewed two books about WikiLeaks for The Sunday Times of London.

When Mr. Hislop pointed out that Mr. Rusbridger was not Jewish, Mr. Assange countered that The Guardian’s editor was “sort of Jewish” because he and Mr. Leigh, who is Jewish, were brothers-in-law. Later, the article recounted, Mr. Assange asked Mr. Hislop to “forget the Jewish thing,” but he continued to insist there was a conspiracy against WikiLeaks based on the friendship among Mr. Rusbridger, Mr. Leigh and Mr. Kampfner.

In the Twitter feed, Mr. Assange said that “in particular” the Private Eye report that he believed in a “ ‘Jewish conspiracy’ is false, in spirit and in word. It is serious and upsetting. Rather than correct a smear, Mr. Hislop has tried to justify one smear with another.”

“That he has a reputation for this, and is famed to have received more libel suits in the U.K. than any other journalist as a result, does not mean that it is right,” Mr. Assange’s statement said. “WikiLeaks promotes the ideal of ‘scientific journalism’ — where the underlying evidence of all articles is available to the reader precisely in order to avoid these type of distortions. We treasure our strong Jewish support and staff, just as we treasure the support from pan-Arab democracy activists and others who share our hope for a just world.”

After Mr. Assange was accused of sexual abuse by two women in Stockholm last summer, he cited a “smear campaign” against WikiLeaks. A London court ruled last week that he must be extradited to Sweden to face questioning on those accusations.