South Korea told its military to increase its vigilance, warning of North Korean provocations, while an official said yesterday that Washington has given the South evidence showing that the North might be reprocessing spent nuclear fuel rods.
Reprocessing the rods would be a key step toward producing nuclear weapons.
The official, who spoke on condition of anonymity, said a US spy satellite photograph showed smoke coming from radiation and chemical laboratories in the North's Yongbyon nuclear complex. However, the official said other telltale signs of nuclear activity, chemical traces or heat signatures, had not been detected.
Meanwhile, after assuring the White House for months that North Korea had not begun producing plutonium for nuclear weapons, US intelligence officials changed their assessment last month, concluding that the country may have produced relatively small amounts, according to senior administration and intelligence officials.
The new assessment was delivered to the White House in mid-April, after President George W. Bush's National Security Adviser Condoleezza Rice ordered a review of the intelligence. A little more than a week later, North Korean officials, meeting with the US in Beijing, boasted that they had already turned 8,000 spent nuclear-fuel rods into weapons-grade material, and strongly hinted they would export it unless they struck a satisfactory deal with the US.
However, US and South Korean officials said they could not verify the claim and suggested North Korea may be bluffing in an attempt to increase its leverage in talks with the US over its suspected nuclear weapons programs.
The history of intelligence gathering in North Korea features numerous major mistakes, both failures to detect major nuclear projects before they turned into major programs and alarms about developments that, on further inspection, proved unthreatening.
The changed assessment reflects the inexact nature of intelligence about North Korea, as well as continuing questions about its true capabilities. But the possibility that the North is already reprocessing nuclear material -- and thus could soon begin producing weapons beyond the two the CIA believes it manufactured more than a decade ago -- is bound to change the tenor of Bush's meetings in the next two weeks with the leaders of South Korea and Japan.
South Korean President Roh Moo-hyun travels to the US on Sunday to meet Bush. The two leaders will discuss a response to a North Korean proposal, floated during the Beijing talks, to end the nuclear dispute.
Though the proposal has not been made public, it is believed that North Korea offered to end its nuclear activities in exchange for economic aid and a security guarantee from Washington.