Labour claims that no perpetrators of the Munich massacre are buried where Jeremy Corbyn attended a wreath-laying ceremony have been cast into doubt by an article from a leading Palestinian political party.

Fatah’s official Facebook page carries a tribute to Atef Bseiso, who is buried at the cemetery in Tunisia, stating that he was involved in planning the “Munich operation”.

Mr Corbyn’s supporters insist no one linked to the 1972 Munich atrocity is buried at the cemetery, while a Labour complaint to press regulator IPSO argues that news coverage suggesting they are is misleading.

The Facebook post in question is a biography of Bseiso, charting how he joined Fatah aged 17 and was nominated for military training in Syria.

Dated December 2016, the post states: “He joined in the planning of the Munich operation.”

The post also sets out how Bseiso worked with “security officials like Ali Hassan Salameh”, who was operations chief for Black September, the group behind the Munich attack which left 11 Israeli athletes dead.

It then records how Bseiso was killed at The Meridian Hotel in Paris in 1992, with Israeli intelligence organisation Mossad accused of the assassination.

The Jeremy Corbyn wreath-laying story Show all 3 1 /3 The Jeremy Corbyn wreath-laying story The Jeremy Corbyn wreath-laying story Atef Bseiso Facebook tribute The tribute to Atef Bseiso on Fatah's official Facebook page The Jeremy Corbyn wreath-laying story Corbyn wreath laying Labour leader Jeremy Corbyn attends the ceremony at the cemetery in Tunisia in 2014 where Atef Bseiso is buried Ambassade de Palestine en Tunisie/Facebook The Jeremy Corbyn wreath-laying story Benjamin Netanyahu Israeli prime minister Benjamin Israel has attacked Mr Corbyn over his attendance at the event Reuters

Fatah is the largest party in the Palestine Liberation Organisation (PLO), the umbrella group for which Bseiso was head of intelligence before he was assassinated.

The PLO, who had tasked Bseiso with building relations with western intelligence agencies, denied at the time of his death that he had any connection to the Munich attack, while Israeli officials said he was involved in that and other terror operations.

Mr Corbyn’s role in a 2014 wreath-laying ceremony was thrust into the spotlight when pictures emerged of him holding a wreath near a plaque honouring Palestinians linked to Black September, the terrorist group behind Munich.

The Labour leader said he only laid a wreath in memory of victims of a 1985 Israeli air strike on a Palestinian base in Tunisia, and while he admitted being “present” while a wreath was laid in honour of those linked to Black September, including Atef Bseiso, he said he did not “think” he had done so himself.

Labour has since insisted that those who perpetrated the Munich atrocity are not even buried in the cemetery, and have used the argument as part of their complaint to IPSO.

The Independent provided Mr Corbyn’s office with a link to the Facebook post and the Arabic text, along with an English translation.

Jeremy Corbyn: I was “present” when the wreath was laid “I don’t think I was actually involved in it.”

A spokesman said: “Jeremy visited the Palestinian National Cemetery to attend the annual commemoration of those killed in the illegal, UN-condemned airstrikes on the PLO headquarters in 1985.

“He did not commemorate Atef Bseiso or [any] other PLO leader buried in the cemetery.”