Labour’s deputy leader Tom Watson has accused a member of the party’s ruling body of being a “loud-mouthed bully” – after he was recorded criticising members of the Jewish community.
The National Executive Committee’s Peter Willsman suggested Jewish “Trump fanatics” were behind accusations of anti-Semitism in the party.
Mr Watson tweeted to say he was disgusted by the comments.
Mr Willsman, a supporter of Labour leader Jeremy Corbyn, has apologised.
Earlier this month, more than 60 British rabbis signed an open letter that said anti-Semitism in the sections of the Labour Party was “severe and widespread”.
That letter followed criticism of the party’s new code of conduct on anti-Semitism, which critics claimed did not sign up fully to the International Holocaust Remembrance Alliance’s working definition.
In a recording published by the Jewish Chronicle, Mr Willsman can be heard discussing the rabbis’ open letter with other NEC members.
Mr Willsman said he did not want to be “lectured to by Trump fanatics”, and argued the NEC should ask the rabbis for “evidence of severe and widespread anti-Semitism” in the party.
Mr Willsman then asked those at the meeting to raise their hands if they had witnessed anti-Semitism in the Labour party – and said he was “amazed” when some said they had.
Following the publication of the recording, the NEC member said he had supported “the decision to confirm the adoption of the code of conduct on anti-Semitism and to reopen development of the code in consultation with Jewish community organisations”.
He added: “Not all of what I said has been accurately reported.
“But I accept that what I did say, and the way I said it, fell short of the requirement, which I accept, for discussions of contentious issues to be conducted in a fully civil and respectful way.
“I deeply apologise for any offence caused to those present and those to whom my remarks were reported.”
The NEC, which acts as Labour’s governing body, oversees the direction of the party and its policy-making process.
The publication of the recording comes amid the NEC’s ongoing elections, which run until 30 August.
Those elected to the committee will serve two-year terms.
Columnist and Labour supporter Owen Jones tweeted to say there was now “no way” he would vote for Mr Willsman, who is one of nine candidates backed by Momentum – the pro-Corbyn grassroots group.