In an unprecedented climbdown, a government spokesman admitted there was "no scientific evidence" to support yesterday’s statement that North Korea had reprocessed all its spent nuclear fuel rods.
President Roh Moo-hyun's foreign policy adviser, Ban Ki-moon, told a meeting of presidential secretaries there was no proof for such a claim.
"We're not at the stage of being able to confirm anything … there is no scientific evidence Pyongyang had completed reprocessing."
Ki-moon’s comments, recorded in minutes of a meeting held in the President’s office, come after South Korea's Yonhap news agency printed a comment made by a former senior aide to the previous South Korean President Kim Dae-jung.
The source, Chang Sung-min, said UN-based North Korean diplomats had informed US officials reprocessing had been completed in June at the North's Yongbyon nuclear complex.
"North Korean delegates told US officials in an unofficial meeting in New York on 8 July that the reprocessing of spent fuel rods was completed on 30 June," Chang was quoted as saying.
Reprocessing the 8,000 spent nuclear fuel rods would enable North Korea to extract 25 to 30 kg of plutonium – enough, say experts, to manufacture at least five nuclear weapons.
But Ki-moon has made it clear he does not know where the evidence for this completed reprocessing intelligence comes from.
Washington and Seoul are trying to draw Pyongyang into talks with South Korea, Japan and China.
The aim is to try to negotiate an end to North Korea's nuclear weapons ambitions. Pyongyang says there must be North Korea-US talks first.
US intelligence hazy
Seoul and Washington are exchanging information on the reprocessing reports, but the US is in a great deal of uncertainty about the state of North Korea's reprocessing.
Rumsfeld: We do not have good
visibility into what they're doing
US Secretary of Defence Donald Rumsfeld told the US NBC television programme "Meet the Press" on Sunday: "We do not have good visibility into what they're doing with those rods, and the extent to which they are or are not reprocessing".
Referring to Pyongyang's statements on weapons possession and reprocessing, Rumsfeld was spectacularly unclear. "Some people believe what they're saying. Other people don't believe what they're saying."
Some reprocessing has happened
Seoul's intelligence agency told parliament last week it estimated the North had reprocessed some of the rods.
On Saturday, Japan's Kyodo news agency cited US sources as saying air samples taken close to Yongbyon had shown traces of krypton 85, a reprocessing by-product.
The uranium rods were part of a programme developed under a 1994 nuclear agreement between North Korea and the United States.
The pact fell apart after Washington said Pyongyang had a covert scheme to enrich the uranium for bombmaking.