A Labour MP stormed out of a press conference staged by Jeremy Corbyn after being accused of colluding with the right-wing press by one of the leader's grassroots supporters.
A clearly upset Ruth Smeeth had been at the launch of a report into anti-Semitism in the party when it was claimed she was in cahoots with The Daily Telegraph.
The row overshadowed the launch, which was sparked by former London mayor Ken Livingstone's controversial comments about Jews.
Mr Corbyn, meanwhile, who is under intense pressure to fall on his sword, refused to answer questions about his leadership.
The review, carried out by Shami Chakrabarti, found the Labour Party "is not overrun by anti-Semitism, Islamophobia or other forms of racism".
But Labour members should "resist the use of Hitler, Nazi and Holocaust metaphors", it says.
Mr Corbyn denied comparing the state of Israel to Islamic State after saying Jews and Muslims should not be held responsible for the actions of either.
Marc Wadsworth, who runs Momentum Black Connexions, claimed that Ms Smeeth, who is Jewish, was "working hand in hand" with the newspaper.
The MP, who is Jewish, walked out of the event as an apparently impervious Mr Corbyn ignored the allegations and talked about the contents of the report.
"This report is about changing the party, it is about race diversity," he replied.
Mr Corbyn has insisted he condemns "any abuse of MPs of any kind".
But he faced criticism for his handling of the debacle as Labour MPs spoke out in support of Ms Smeeth.
Jess Phillips said: "No wonder my brilliant Jewish colleague @RuthSmeeth is in tears when attacked at a speech about antisemitism."
Wes Streeting said: "You sat there and watched our colleague Ruth Smeeth abused at a Labour event this morning. Your words are hollow."
Mr Corbyn said: "Our Jewish friends are no more responsible for the actions of Israel or the Netanyahu government than our Muslim friends are for those of various self-styled Islamic states or organisations. Nor should Muslims be regarded as sexist, anti-Semitic or otherwise suspect, as has become an ugly Islamophobic norm."
Asked if he was comparing Israel and Islamic State, he replied "of course not".
He said: "The point in the report is you shouldn't say to somebody just because they are Jewish you must have an opinion on Israel any more than you would say to anyone who is a Muslim you must have an opinion on any vile actions that have been taken by misquoting the good name of Islam in what they do."
Ms Chakrabarti was brought in at the height of a row over alleged racist remarks that resulted in several high-profile figures being suspended, including MP Naz Shah and former London mayor Mr Livingstone.
But the review did not make any recommendations about his future in the party.
Mr Corbyn, who faced allegations of not taking the situation sufficiently seriously, tasked the former Liberty director with helping set ''boundaries of acceptable behaviour and language'' and strengthening structures for dealing with racism of all forms.
It recommended that Labour members should not use terms like "Paki" or "Zio" and should steer clear of invoking Hitler, particularly in debates about Israel and Palestine.
"The Labour Party is not overrun by anti-Semitism, Islamophobia, or other forms of racism," it added.
James Sorene, chief executive of the Britain Israel Communications and Research Centre think tank, criticised the report's findings.
He said: "We regret that the inquiry has failed to recognise the dangerous, systematic demonisation of Israel by those Labour Party members who cross the line into anti-Semitism and attempt to disguise it as anti-Zionism. There are sadly no recommendations for new measures to allow them to be removed as members and the inquiry effectively offers an amnesty, which it calls a moratorium, to those who have used anti-Semitic language in the past.
"The report is vague and indecisive on action against members who indulge in anti-Semitic anti-Zionism, and dismisses a culture of systematic demonisation of Israel as a 'series of unhappy incidents'.
"If you portray the existence of Israel as a crime and indulge dangerous fantasies about the country no longer existing, that is anti-Semitic and deeply offensive. There is a constructive debate about how to reach a peaceful resolution to the Israeli-Palestinian conflict in the UK of which we are part, and this is not it.
"Criticising the Government of Israel is of course entirely legitimate as it is for any Government. But when that criticism is expressed in violent language, directed at its people in racist terms or uses references to Hitler and Nazism, it is anti-Semitic and deeply offensive. As such we are encouraged that the inquiry recommends references to Hitler and Nazism should be resisted in this context."