Jeremy Corbyn has faced condemnation after footage emerged of him drawing comparisons between the Nazi occupation of wartime Europe and Israeli actions in the West Bank.
The Labour leader said the area was under “occupation of the very sort” that would be recognised by many people in Europe who suffered occupation during the Second World War.
Labour Friends of Israel, which campaigns for a two-state solution, called the comments “appalling”.
But the Labour Party insisted Mr Corbyn was not comparing the Israeli State with Nazis.
Mr Corbyn called for the history of the Middle East to be taught in a “more accurate and more balanced way” and said Palestinians had been systematically demonised since the First World War.
The Labour leader said the conflict between Israel and Palestine was portrayed as one between equal powers when it is not in the video posted on Twitter by anonymous account “The Golem”.
It said Mr Corbyn was addressing an event hosted by the Palestinian Return Centre, which describes itself as an independent consultancy for Palestinian refugees, in 2013.
“The Palestinian people are generally very poor and in the case of Gaza, virtually imprisoned within that very small area and facing environmental disaster and catastrophe.
“And in the West Bank, under occupation of the very sort that would be recognised by many people in Europe who suffered occupation during the Second World War, with the endless road blocks, imprisonment, irrational behaviour by the military and the police.”
It comes after the account tweeted footage earlier in the week showing Mr Corbyn appearing to query the right of Israel to exist.
Labour’s leadership faced a backlash when it endorsed the International Holocaust Remembrance Alliance’s (IHRA) working definition of anti-Semitism but omitted some of the examples of behaviours likely to be regarded as anti-Semitic that accompanied it.
Comparing contemporary Israeli policies with those of the Nazis was among the examples left out by the party.
Jennifer Gerber, director of Labour Friends of Israel, said: “Earlier this week, we discovered that Jeremy Corbyn engaged in wild conspiracy theories questioning Israel’s right to exist.
“Today, it is revealed he drew comparisons between conditions in the West Bank and the Nazi occupation of Europe.
“It is increasingly clear that his opposition to adopting the IHRA definition in full appears to be overwhelmingly driven by his own appalling past statements.
“The Labour party’s once proud record on fighting racism and the protection of British Jews from anti-Semitism is being sacrificed to protect Jeremy Corbyn’s reputation.”
Labour argues that anti-Semitic behaviours omitted from its list are covered elsewhere in the document in a way which will make it easier to take disciplinary action.
Jewish leaders earlier warned Mr Corbyn that the anti-Semitism row engulfing Labour is not going away and called on him to “come out of hiding”.
The Board of Deputies of British Jews accused the Labour leader of refusing to face difficult questions about his response to the issue and hoping it would disappear.
President Marie van der Zyl also claimed Mr Corbyn had attempted to “divide and rule” British Jews with a “botched” plan to address some representatives at the Jewish Museum while failing to invite other key groups.
In an article for the Jewish News, she wrote: “He is clearly just hoping it will go away. I’ve got some bad news for him – unless he does what he needs to do, it won’t.”
Mrs van der Zyl said Labour must accept the international definition of anti-Semitism and all of the examples set out by the IHRA.
She called for Mr Corbyn to “own up” to the “problematic nature” of his own past actions as well as for transparency in the party’s disciplinary process.
Labour has declined to set out the party leader’s summer holiday plans but Mr Corbyn was pictured in the Sun at the Lion Rock Tea Rooms in Cheddar, Somerset.
Mrs van der Zyl said it was time for him to publicly deal with the issues in the party, warning “you cannot lead through invisibility”.
“I call on Jeremy Corbyn to come out of hiding and do the right thing,” she wrote.
“Surely, by now, enough is enough.”
A Labour spokesman said: “Jeremy was describing conditions of occupations in World War Two in Europe, of which there are multiple examples, not comparing the Israeli State to Nazis.”