Shadow chancellor John McDonnell has been criticised over a speech in which he described Israeli attacks on Gaza as attempted genocide.

But the Labour MP made clear he would not back down from his comments, releasing a statement which said he “takes pride” in his record of condemning brutality against Palestinians.

The row came amid continuing controversy over Labour’s position on anti-Semitism, with the Jewish News reporting that Momentum founder Jon Lansman had been lobbying the party’s leadership for weeks to adopt the International Holocaust Remembrance Alliance definition in full.

Sources close to Mr Lansman – whose movement has been strongly supportive of Jeremy Corbyn – told the paper he “regretted” that the Labour leader had not offered “a firm commitment” to adopt in full the definition and its list of examples of anti-Semitic behaviour.

Mr McDonnell’s comments, in a speech in 2012, were highlighted by the Daily Telegraph, which also drew attention to his 2016 appearance on a platform alongside activist Jackie Walker, who was suspended by Labour for alleged anti-Semitism.

Speaking to a Unite the Resistance event at a time of intensive Israeli airstrikes on the Gaza enclave, Mr McDonnell said: “It’s absolutely critical now that we use every platform we can to expose what’s going on, which is effectively an attempt at genocide against the Palestinians.”

Karen Pollock, chief executive of the Holocaust Educational Trust, told the paper his remarks were “not only inaccurate, but irresponsible and deeply offensive”.

Mr McDonnell accused the Telegraph of “doing a number” on him.

He released a statement saying: “Our response: ‘John takes pride in and stands by his track record of forcefully and justifiably condemning brutal attacks on the Palestinian men, women and children of Gaza  and will always stand up for victims of such disproportionate violence’.”