Labour leaders fighting to become a key party powerbroker are getting bogged down in a vicious war of "anti-Semitism" allegations.

Jennie Formby condemned "anti-Semitic" social media attacks on her rival Jon Lasman, who has also been labelled as a "Zionist" on Twitter.

Now, another Labour group is accusing Formby, who ran saying the party should have "no place for anti-Semitism", of being anti-Semitic herself.

When Iain McNicol shocked party staff by dramatically stepping down as general secretary last week, Formby announced that she would be running to succeed him.

Momentum founder Lasman, who is Jewish and has been accused of being a Zionist by a number of Labour supporters, was reportedly urged by allies to run as the "stop Formby" candidate, according to PoliticsHome.

Lasman announced that he would be throwing his hat into the ring "to open the contest and ensure we have a wide range of candidates", despite days of pressure from senior party figures, including Labour leader Jeremy Corbyn.

Supporters of Formby, who include Shadow Chancellor John McDonnell and other senior members on the front bench, fear Lansman could split the left-wing vote and allow a more moderate candidate to win.

Others are using Lansman's apparent views on Israel to try to stop him from running for general secretary.

One person tweeted: "Get rid of zionist infiltrator @jonlansman he is the enemy within. His objectives are divide and conquer. Lets see his tax returns."

While someone else said: "Isn't Momentum supposed to exist as a collective who believe in Corbyn as leader and his policies. How is going against him when he has chosen his candidate.. part of Momentum's aims and mission statement ?"

Formby addressed the abusive tweets on her own Twitter account, defending her colleague by writing: "Just seen anti-Semitic attacks on @jonlansman. They are disgraceful and must stop. This sort of abuse has no place in the Labour Party #NotInMyName."

She also told PoliticsHome: "These attacks on a colleague are disgraceful and must cease. This abuse has no place in the Labour party."

When she announced her candidacy in a statement, Formby said that she stood for "a tolerant and welcoming party, with no place for anti-Semitism, racism and misogyny or any form of abuse or intimidation".

Meanwhile, the Labour Against Anti-Semitism (LAAS) has accused Unite official Formby of being anti-Semitic, claiming she had "acted with anti-Semitic intent".

She allegedly objected to an inquiry into anti-Semitism being carried out by Baroness Royall on the grounds that the Labour peer was a member of the Labour Friends of Israel group.

Unite released a strongly-worded statement in response and called the accusation a "malicious smear."

The statement read: "Jennie Formby voted for Ms Jan Royall's appointment, and argued for her inquiry to be properly resourced by the party.

"Ms Formby is a lifelong opponent of antisemitism and all forms of racism. LAAS's smears have no place in Labour's democracy or political culture."