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

On 1993, South African president F.W. de Klerk made an announcement about the building of 6 nuclear weapons. Many have studied the reasons for the dismantling and among the reasons is that the government scrapped the program because of fear that the weapon will be misused by black-majority-government. 

japan

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