Jeremy Corbyn was embroiled in a fresh antisemitism row on Friday after conceding he was wrong to support a graffiti artist whose “offensive” work was scrubbed off a wall in London’s East End.

In a Facebook post in 2012, Corbyn offered his backing to Los Angeles-based street artist Mear One, whose mural, featuring several known antisemitic tropes, was due to be removed after complaints.

Mear One said on his Facebook page: “Tomorrow they want to buff my mural Freedom of Expression. London Calling, Public art.”

Corbyn replied: “Why? You are in good company. Rockerfeller [sic] destroyed Diego Viera’s [sic] mural because it includes a picture of Lenin.”

“In 2012, Jeremy was responding to concerns about the removal of public art on the grounds of freedom of speech,” said a statement released by the Labour party on Friday. “However, the mural was offensive, used antisemitic imagery, which has no place in our society, and it is right that it was removed.”

The mural, which was subsequently scrubbed off, pictured several apparently Jewish bankers playing a game of Monopoly, with their tabletop resting on the bowed naked backs of several workers.

Labour MP Luciana Berger raised the issue with Corbyn’s office after screenshots of the Facebook post emerged. She said on Friday afternoon that she was not satisfied with the statement issued by the Labour press office.

The response from the Spokesperson is wholly inadequate. It fails to understand on any level the hurt and anguish felt about Antisemitism. I will be raising this further. — Luciana Berger (@lucianaberger) March 23, 2018

Corbyn’s office then released a second statement – shortly after announcing the sacking of the shadow Northern Ireland secretary, Owen Smith. In it, Corbyn said he had made, “a general comment about the removal of public art on grounds of freedom of speech”.

He said the case he cited, in which a mural by Mexican artist Diego Rivera in New York’s Rockefeller centre was plastered over, was “in no way comparable” with the mural in the Facebook post.

“I sincerely regret that I did not look more closely at the image I was commenting on, the contents of which are deeply disturbing and antisemitic,” he said. “The defence of free speech cannot be used as a justification for the promotion of antisemitism in any form. That is a view I’ve always held.”

Corbyn has been accused of failing to crack down on a series of cases of antisemitism.

He recently admitted being a member of a closed Facebook group called Palestine Live, in which a number of antisemitic posts appeared – though he did not join in the conversations and left the group in 2015.

When the existence of the group was revealed earlier this month, Corbyn told reporters: “Had I seen it, of course, I would have challenged it straight away, but I actually don’t spend all my time reading social media.

After Friday’s incident, Labour peer and former Ed Miliband adviser Stewart Wood said: “The German Social Democrats had an expression in the 1890s: ‘antisemitism is the socialism of fools’. Sadly, Labour’s leadership now faces the challenge of having to convince our party and country that they will not tolerate those who confuse the two.”

Dudley MP Ian Austin said the mural was one of the worst antisemitic images he had seen. “Jeremy would never have defended racist imagery aimed at any other group,” he said.

Some Labour MPs have also expressed concerns about the longrunning case of Ken Livingstone, who remains suspended over a series of controversial remarks.

At prime minister’s questions, on Wednesday, Theresa May sought to capitalise on the issue in the run-up to May’s local elections.

“The message is clear: if you believe in good local services, want to see more homes built and want to tackle antisemitism, there is no place for you in the Labour party,” May said.

But some of Corbyn’s allies, including Derby North MP Chris Williamson, have suggested that the issue of antisemitism is being “weaponised” by those critical of Corbyn’s leadership.