The document, released at the request of the security studies centre at Georgetown University in Washington, says a mystery explosion detected on September 22, 1979 by a US satellite was a nuclear test.

Prepared for the White House in December 1979, it said Israel and South Africa, then under apartheid rule, were cooperating on military issues, including nuclear research.

US intelligence services reported in 1990 that South Africa was producing nuclear weapons, while Israel is estimated to possess 200 nuclear warheads, although it has never confirmed or denied holding such weapons. South Africa later dismantled its nuclear weapons program under UN supervision.

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