Labour has defended Jeremy Corbyn's approach to complaints of growing anti-Semitism within the party after the Board of Deputies of British Jews launched a fresh accusation of inaction.
President Jonathan Arkush issued a strongly-worded statement criticising what he said was the Opposition leader's "deeply disturbing" defence of comments made at the weekend by his brother.
Piers Corbyn dismissed as "absurd" a complaint by MP Louise Ellman, who is herself Jewish, that the party leader had failed to act on promises to stamp out abuse.
Her comments came after a series of incidents involving anti-Semitic comments by Labour activists including one who was suspended after posting a series of tweets referring to Jews with "big noses" and describing Hitler as a "Zionist God".
"JC+ All Corbyns are committed AntiNazi," Piers Corbyn posted on Twitter after her intervention in a TV interview.
"Zionists cant cope with anyone supporting rights for Palestine."
Asked about the post, the Labour leader told The Sun: "No, my brother isn't wrong.
"My brother has his point of view, I have mine and we actually fundamentally agree - we are a family that were brought up fighting racism from the day we were born."
He went on: "We're opposed to any form of racism and we are investigating allegations of anti-Semitism, but I wouldn't call it a crisis, we are a party are taking resolute action."
Mr Arkush said his response suggested a failure to take the issue sufficiently seriously.
"Jeremy Corbyn's defence of his brother's belittling of the problem of anti-Semitism is deeply disturbing," he said.
"We cannot imagine that any other minority's concerns would be dismissed off-hand in this way. In the last few weeks we have witnessed a stream of clear-cut cases of anti-Semitism in the Labour Party, which can't just be fobbed off as differences over Israel.
"Most of the Jewish community, numerous Labour MPs, Labour peers, and Labour's London mayoral candidate are crying out for the leader to take action on anti-Semitism.
"It would be incomprehensible for Mr Corbyn to remain inert and refuse to take this form of racism in his party seriously."
A spokesman for the Labour leader said: " It is Jeremy Corbyn who is taking action on anti-Semitism.
"He has consistently condemned anti-Semitism and all forms of racism and, under Jeremy Corbyn's leadership, Labour is clamping down on anti-Semitism and taking clear action against offenders.