The disgraced Pakistani nuclear scientist, AQ Khan, has said that allegations he passed on nuclear secrets are false. In a rare interview, he said that there was pressure put on him to accept the charges "in the national interest".
Secret South African documents reveal that Israel offered to sell nuclear warheads to the apartheid regime, providing the first official documentary evidence of the state's possession of nuclear weapons.
The controversial whistle-blowing site Wilileaks has released a cache of 250,000 secret messages sent by US diplomatic staff. Here are some of the key issues the documents reveal, as reported by the New York Times and Guardian newspapers.