The United States is warning allies that North Korea (search) may be ready to carry out an underground nuclear test as early as June, diplomats said Saturday.
The diplomats told The Associated Press that the information apparently had been gathered in part from satellite imagery. They spoke on condition their names not be disclosed, due to the sensitivity of discussing intelligence information.
The reported U.S. warnings reflected growing fears in Washington that the North is going ahead with efforts to develop nuclear weapons after South Korean officials said Pyongyang (search) had recently shut down a nuclear reactor, possibly to harvest plutonium that could be used in an underground test.
The 5-megawatt reactor at Yongbyon (search) generates spent fuel rods laced with plutonium, but they must be removed and reprocessed to extract the plutonium for use in an atomic weapon. They can be removed only if the reactor has been shut down.
North Korea started up its mothballed reactor after quitting the International Atomic Energy Agency (search) in 2002 and expelling U.N. monitors.
The White House declined Saturday to shed any additional light on the conversations U.S. officials are having with allies on North Korea's nuclear intentions.
Spokesman Allen Abney pointed to comments from U.S. President George W. Bush earlier in the week that the United States is determined not to take the next diplomatic step regarding North Korea, referring the matter to the United Nations for possible sanctions, without a concensus with allies in the region.
On Friday, U.S. Assistant Secretary of State Christopher Hill — Washington's point-man on North Korea — warned the communist state against conducting a nuclear test, saying such a move would be a "truly troubling" complication for suspended six-nation talks on halting Pyongyang's nuclear program.
The negotiations — among the two Koreas, the United States, China, Japan and Russia — stalled in June after three inconclusive rounds.
The U.S. mission to the IAEA nuclear agency in Vienna declined comment, and an official close to the IAEA told the AP he was not aware that Washington had informed the agency of the most recent concerns. After the North quit the IAEA in 2002, the agency was left with no direct access to or overview of the country's nuclear program.
The U.S. intelligence community believes North Korea has one or more nuclear weapons, and has untested two- and three-stage missiles capable of reaching U.S. soil. But it has been unclear whether Pyongyang has yet developed the technology to miniaturize a nuclear weapon so it fits on a missile, and provide it with the guidance systems so it can hit a target.
The United States and South Korea have called on China — the North's major ally — to play a bigger role in convincing Pyongyang to return to the negotiations.
South Korean President Roh Moo-hyun plans to discuss the standoff with his Chinese counterpart, Hu Jintao, in Moscow on May 9 during Russia's celebration of the 60th anniversary of the Allied victory in Europe.
Resuming the six-nation talks gained urgency in February when the North claimed it already has produced nuclear weapons and would boycott further negotiations.