The Nelson Mandela Foundation has hit out against claims that the former South African leader was trained by Israeli secret service agents in 1962.

A top secret letter reportedly located in Israeli state archives and published in the Tel Aviv-based newspaper Haaretz weeks after Mandela's death claims that the anti-Apartheid icon underwent weapons training by Mossad in Ethiopia under an assumed identity.

According to the letter, Mandela received instruction in sabotage techniques and the use of weapons, and was encouraged to develop Zionist sympathies without the Israeli secret services knowing his true identity.

"The Nelson Mandela Foundation can confirm that it has not located any evidence in Nelson Mandela's private archive that he interacted with an Israeli operative during his tour of African countries in that year," the foundation said in a statement.

In 1962, Mandela visited a number of African countries in an effort to gather support for the anti-Apartheid movement spearheaded by the African National Congress in South Africa.

According to the letter, Mandela solicited help from the Israeli embassy under a pseudonym while he was in Ethiopia. The document is reported to have been sent to officials in Israel in October 1962 with the subject line 'Black Pimpernel' – a term the South African press used to refer to Mandela.

Haaretz quoted the paper as saying: "As you may recall, three months ago we discussed the case of a trainee who arrived at the [Israeli] embassy in Ethiopia by the name of David Mobsari who came from Rhodesia.

"The aforementioned received training from the Ethiopians [a codename for Mossad agents, according to Haaretz] in judo, sabotage and weaponry."

It added that "David Mobsari" showed interest in the methods employed by Haganah, a Jewish paramilitary organisation that fought against Palestine's Arab population during the 1930s and 1940s.

The Nelson Mandela Foundation dismissed these claims, however, adding: "In 1962, Mr Mandela received military training from Algerian freedom fighters in Morocco and from the Ethiopian Riot Battalion at Kolfe outside Addis Ababa, before returning to South Africa in July 1962.

"In 2009, the Nelson Mandela Foundation's senior researcher travelled to Ethiopia and interviewed the surviving men who assisted in Mandela's training – no evidence emerged of an Israeli connection."

Israel's ministry of foreign affairs website refers to a meeting between Mandela and an "unofficial Israeli representative" in Ethiopia in 1962, but it does not explicitly mention any training from Mossad.