The leader of Britain’s left-leaning Labour Party is facing intensifying criticism from outsiders and some of his own members for what is viewed as a failure to address reports of anti-Semitism involving some Labour supporters.

Allegations of anti-Semitism within Britain’s main opposition party have grown since Jeremy Corbyn, a longtime critic of Israeli actions against the Palestinians, was elected leader in 2015.

The simmering tensions — which already had cost Labour some backing — escalated Sunday with newspaper reports about numerous anti-Semitic Facebook posts from groups that support the party.

The Sunday Times reported that some senior Labour staff workers were members of Facebook groups that made anti-Semitic and violent comments.

Labour has denied the groups named by the Sunday Times are connected to the party in any way. Corbyn maintains the party has “zero tolerance” for anti-Semitism and other forms of discrimination.

While friction between Jewish advocacy groups and Corbyn has existed almost since the start of his reign, the latest confrontation began when a 6-year-old Facebook posting was brought to public attention last month by a Labour Party lawmaker who is Jewish.

In the post, Corbyn expressed support for an artist who created a street mural that included a number of anti-Jewish stereotypes.

After lawmaker Luciana Berger questioned the posting on March 23, Corbyn said he regretted not looking closely at the “deeply disturbing and anti-Semitic” mural before encouraging the artist.

His stewardship of the party has been criticized by longtime Labour activist David Garrard, a major donor who told The Observer newspaper he has left the party because of its failure to confront anti-Semitism.

Garrard said the party has failed to expel members espousing “the grossest derogatory” comments about alleged Jewish conspiracies and characteristics.

“I have watched with dismay and foreboding the manner in which the leadership has, in my view, over the last two years, conducted itself,” he said. “I consider that it has supported and endorsed the most blatant acts of anti-Semitism.”

The Board of Deputies of British Jews and the Jewish Leadership Council say Corbyn’s party has repeatedly failed to deal with anti-Semitism.

On Saturday, senior Labour official Christine Shawcroft resigned from the party’s National Executive Committee after she was criticized for opposing the suspension of a Labour Party council candidate who was accused of Holocaust denial. Shawcroft said her presence on the leadership board had become a “distraction.”

She was replaced on the leadership committee by actor-comedian Eddie Izzard, who on Sunday acknowledged Labour’s rift with Britain’s Jews.

“We must make amends and repair the damage with the Jewish community as Jeremy Corbyn has promised to do,” Izzard said.

(AP)