The Nelson Mandela Foundation says it has no evidence that the anti-apartheid icon received training from Israel's Mossad agency in 1962.
Israel's Haaretz newspaper reported this week that intelligence documents from Mossad indicated the spy agency had given Mandela weapons training in Ethiopia.
"In 2009, the Nelson Mandela Foundation's senior researcher travelled to Ethiopia and interviewed the surviving men who assisted in Mandela's training," the foundation said on Saturday.
"No evidence emerged of an Israeli connection."
The foundation, which works to preserve Mandela's legacy, also said nothing in Mandela's private archive, including his diaries, indicated he had interacted with Mossad agents during his tour of African countries in the early 1960s when he sought training and support to bolster the armed resistance to apartheid.
Israel had developed close links with Ethiopia's dictator at the time, Haile Selassie, the last emperor of the country, who was overthrown in a 1974 coup.
Israel later forged a tight bond with the apartheid regime in South Africa, including in nuclear affairs.
Its ties with South Africa were strained after the white-minority regime collapsed and Mandela became the country's first black president.
His governing African National Congress is a staunch supporter of Palestinian statehood, and Mandela frequently voiced his allegiance to the Palestinian cause.
According to a letter reported in Haaretz, Mandela was given military training and was encouraged to develop Zionist sympathies.
The foundation confirmed Mandela received arms training in Morocco from Algerian fighters who rebelled against French colonial rule and in Ethiopia from Ethiopian forces.
