Labour leader Jeremy Corbyn has said “people who dish out anti-Semitic poison need to understand: you do not do it in my name”.
In an article for the Guardian, he said anti-Semitism was a “real problem” that Labour was “working to overcome”.
But he did not give in to demands to adopt all the examples of anti-Semitism cited by the International Holocaust Remembrance Alliance (IHRA).
Critics in the Labour Party said the article had changed nothing.
In his article, he said he recognised the “strong concerns” about Labour’s code of conduct and that many Jewish organisations believed it should include all 11 examples of contemporary anti-Semitism cited by the IHRA in its guidelines.
Mr Corbyn, a long-standing supporter of the rights of Palestinians, defended Labour’s decision not to include one of the examples – which warns against “claiming that the existence of a State of Israel is a racist endeavour”.
He said this had “sometimes been used by those wanting to restrict criticism of Israel that is not anti-Semitic”.
But he added: “I feel confident that this outstanding issue can be resolved through dialogue with community organisations, including the Jewish Labour Movement, during this month’s consultation.”
The Labour leader also wrote that he would “not for one moment accept that a Labour government would represent any kind of threat” to Jewish life in the UK.
“That is the kind of overheated rhetoric that can surface during emotional political debates,” he said.
By Susana Mendonca, BBC political correspondent
This was supposed to be Jeremy Corbyn reaching out to the Jewish community to repair frayed relations.
The tone of some of what he said was conciliatory. He acknowledged the party had a problem with anti-Semitism and accepted the Jewish community should have been consulted earlier on the code of conduct.
But there was no sudden change in policy on the code – and nothing short of that was ever going to silence his critics.
The timing didn’t help either as it was released just before the Jewish Sabbath, leading some to suggest that was intended to avoid reaction from the Jewish community.
Labour tells me that was not the case and the article was supposed to have been published much earlier in the day.
Nonetheless the reaction has come – and it hasn’t been positive.
“Vague and meaningless” was the assessment from the Campaign Against Antisemitism.
Expect this row to continue rumbling on through this long hot summer.
Labour MP Ian Austin, who is being investigated over his alleged behaviour during a row about the party’s code of conduct, said Mr Corbyn’s article will “make matters much worse”.
“Under his leadership, the Labour Party has caused huge offence and distress to the Jewish community yet he’s not just completely failed to make a single change, but repeated some of the things that have caused this problem,” he said.
Another Labour MP, Wes Streeting, a leading critic of Mr Corbyn’s stance on anti-Semitism, told the BBC his party leader was guilty of “the same old hand wringing we’ve heard time and time again”.
A Jewish Labour Movement spokesperson said: “Today, other than another article bemoaning a situation of the party’s own making, nothing has changed. There is no trust left. We find ourselves asking once again for action, not words.”
But Barnaby Raine, a Jewish Labour party member and supporter of Mr Corbyn, told BBC Radio 4 that the article demonstrated a significant step forward for the leader.
“He has acknowledged that anti-Semitism is a serious problem in the Labour party,” he said. “He has taken on those people that say that they support him, even though they are anti-Semities.
“And he has done something… which I think this is especially important – he has condemned those people, not just who hold anti-Semitic attitudes, but who dismiss this whole thing as just a smear on the Labour party.”
‘Still no wiser’
Earlier it emerged that Labour had offered to drop disciplinary action against Dame Margaret Hodge if she issued an “appropriate apology” over an anti-Semitism row.
The party launched an investigation into the veteran Labour MP after a confrontation she had with Mr Corbyn.
She has published letters on social media between her lawyers and Labour’s general secretary, Jennie Formby.
“I’m still no wiser as to what I’m accused of; the nature of complaints received; who the investigating officer is; or what the time frame for the investigation will be. Is this fair?,” Dame Margaret said.
Solicitors from Mischon de Reya, which is acting for Dame Margaret, have told the Labour Party either to proceed with the investigation or to drop it, and if not, they have warned that she may take the Labour Party to court.
They also say the Barking MP will not apologise as she does not accept that she breached Labour rules.
Mr Corbyn had been hoping to make a speech addressing the anti-Semitism row at the Jewish Museum, in London, but the museum has now said there are “no plans” for a Labour event there.