The hostility between the two would soon reach boiling point. In the early 1990s, US intelligence intercepted a cache of spent plutonium being extracted from the nuclear reactor at Yongbyon near Pyongyang. The CIA's conclusion was that North Korea's nuclear programme was going very well. US President Bill Clinton threatened sanctions as well as a airstrike that promised to take out the nuclear centrifuges. This was followed by the UN threatening sanctions as well. Pyongyang was seen to be going back on its promise of not going nuclear to the International Atomic Energy Agency (IAEA) .