Tom Watson has vowed to face down a campaign to oust him as Labour’s deputy leader as the party was forced to suspend a veteran activist who made antisemitic remarks criticising Watson’s intervention.

It swiftly suspended George McManus on Monday hours after the Momentum-backed candidate for the national policy forum (NPF) posted a Facebook comment about Watson’s “Jewish donors” and compared him to Judas being paid to betray Jesus.

Momentum has since disowned McManus, calling his comments appalling, and a Labour source said he was no longer on the NPF ballot.

Critics of Watson had caused the hashtag #ResignWatson to trend on Twitter overnight after an Observer interview in which he said Labour faced a “vortex of eternal shame” unless it tackled the antisemitism row.

McManus, who stood for election to lead the body this year, highlighted donations received by Watson from the businessman Sir Trevor Chinn and wrote: “Apparently Watson received £50,000+ from Jewish donors. At least Judas only got 30 pieces of silver.”

Luciana Berger, the MP who leads the Jewish Labour Movement, submitted a formal complaint to the party about the comments, saying it must take “swift action”.

The Facebook post has since been deleted and McManus has apologised. “I’d like to apologise to Tom Watson for my drawing an analogy between him accepting money from Jewish donors and the biblical story of the betrayal by Judas. I fully accept that such an analogy is wrong and am sorry for making the comparison,” he wrote.

Momentum said it was “an appalling, antisemitic comment” made by McManus, adding: “We understand that he has now rightly been suspended from Labour. We will not tolerate any antisemitism, racism or online abuse from candidates we support.”

Watson said the party should end disciplinary action against the MPs Ian Austin and Margaret Hodge, who criticised Jeremy Corbyn’s response to the row, and also said Labour should fully adopt the International Holocaust Remembrance Alliance (IHRA) definition of antisemitism and all its examples.

Labour is preparing to adopt three of the four IHRA examples that had been excluded from the antisemitism definition in the party’s new code of conduct, the Guardian understands, which include comparing Israel’s actions to the Nazis and accusing Jewish people of “dual loyalty” to Israel.

However, an impasse remains over one final example, “claiming that the existence of a state of Israel is a racist endeavour”, because of concerns about hindering legitimate criticism of Israel. Jewish community leaders have insisted the definition should be adopted in full and say it does not prohibit criticism of the actions of the Israeli state.

The former cabinet minister Yvette Cooper also urged the party to adopt the IHRA definition. “I think this problem that we are in is awful for the Labour party that’s got such a history of fighting racism. To be stuck in this mess, it’s an awful situation that we are in,” she told BBC Radio 4’s Today programme.

“I think it is not going to go away until the party adopts the international definition of antisemitism. I support Tom on this. I think the point is we need to address it.”

After his Observer interview was published, Watson tweeted that he had been taken aback by the extent of the backlash.

Tom Watson (@tom_watson) It sometimes feels like people have been calling for me to stand down from day one but I never, ever thought I’d be facing demands to #resignwatson for standing up for people who are facing prejudice and hate.

Matt Zarb-Cousin, a commentator and former Corbyn spokesman, said attacks on Watson had gone too far. “His recent comments come from a place of wanting what’s best for Labour, so we get into government and Corbyn’s PM. That’s not grounds to call for his resignation,” he tweeted. “After he misjudged Jeremy’s ability as leader, he said so. Us activists need to ditch this bunker mentality.”

Over the weekend, Corbyn sought to further defuse the row with a video message apologising for “hurt that has been caused to many Jewish people”.

Play Video 1:15 Jeremy Corbyn: ‘I want Jewish people to feel at home in the Labour party’ - video

“Our party must never be a home for such people and never will be. People who use antisemitic poison need to understand: you do not do it in my name or the name of my party. You are not our supporters,” he said. “And anyone who denies that this has surfaced within our party is clearly actually wrong and contributing to the problem.”

However, Marie van der Zyl, the president of the Board of Deputies of British Jews, and Jonathan Goldstein, the chairman of the Jewish Leadership Council, wrote in a New Statesman article that the Labour leader needed to acknowledge his own “problematic” history.