(JTA) — The Labour Party candidate in London’s mayoral race, a Muslim, said he is “embarrassed” and “sorrowful” about his party’s failure to take on anti-Semitism.

Sadiq Khan, who is of Pakistani descent, said Tuesday in a speech at a London Jewish community center that Labour leader Jeremy Corbyn needs to be “trained about what anti-Semitism is,” Newsweek reported.

Labour has come under increasing attack for its perceived tolerance of members who make anti-Semitic remarks. In an Op-Ed in The Telegraph last Friday headlined “Labour has a serious anti-Semitism problem,” Board of Deputies of British Jews President Jonathan Arkush criticized Corbyn for failing to address adequately the issue.

Last week, the same British newspaper reported that an activist who has described his critics as “Zio idiots” and “Zionist scum,” and has claimed that Jews supported Nazi Germany’s Nuremburg Laws, had been allowed into the party after previously being barred. Also last week Chris Bryant, a Labour member of Parliament and an opposition leader, said the issue of anti-Semitism threatens to destroy the party, while another Labour leader and Parliament member, Michael Levy, threatened to leave the party unless it works harder to address anti-Semitism in its ranks.

“If it needs senior members, including members of the NEC [National Executive Committee], of my party to be trained about what anti-Semitism is, then so be it,” Khan, a minister representing a south London neighborhood, said in his JCC speech. “I think the Labour leadership could have taken a tougher stance — and should have taken a tougher stance. There is no hierarchy when it comes to racism — racism is racism.”

London’s mayoral election takes place May 5. Recent polls show Khan enjoying a narrow lead over Zac Goldsmith, the Conservative Party candidate.

Khan also criticized the use of the term “Zio” as a Jewish slur and noted that anti-Semitism is “not just a problem for the Jewish community, it is a problem for society.”