The unfettered transfer of weapons technology in Asia has possibly already given North Korea the expertise to make two nuclear bombs.
Experts estimated in 1999 that Pyongyang had a 20kg stockpile of plutonium, enough to make one or two weapons - a position supported by the Bush administration. These programmes were frozen under the October 21, 1994, agreement with the US, which put in place International Atomic Energy Agency (IAEA) safeguards.
At the time, the North had a five-megawatt (MW) reactor in Yongbyon, about 90km north of Pyongyang, and was building two others with capacities of 50MW and 200MW.
About 8,000 spent fuel rods were taken from the frozen reactor and sealed in metal cases under the IAEA's supervision. The amount of weapons-grade plutonium that could be extracted from the rods is estimated by experts to be about 20kg. They say it could make one or two nuclear devices.
Under the deal, the reactors would be replaced with light-water power plants while ties with Washington would be restored. Both sides also said they would work to strengthen the nuclear non-proliferation regime.
However, the global lack of resolve on the treaty and other pacts on weapons non-proliferation has created the latest crisis, analysts say. The blame, they add, is on the Bush administration.