What country announced in 1993 that it had built 6 nuclear weapons but they had all been dismantled?

On March 24, 1993, South African President F.W. de Klerk announced publicly that South Africa had built and then dismantled 6 nuclear bombs. The devices were reported to have a similar yield as that of the atomic bomb dropped on Hiroshima in 1945.

In the 1960's to the 1980's, South Africa had pursued research into weapons of mass destruction. Before the anticipated changeover to a majority-elected African National Congress government in the 1990's the South African government dismantled all of its nuclear weapons, the first nation in the world which voluntarily gave up all nuclear arms it had developed itself.

The country has been a signatory of the Biological Weapons Convention since 1975, the Treaty on the Non-Proliferation of Nuclear Weapons since 1991, and the Chemical Weapons Convention since 1995.