SEOUL, South Korea -- South Korea said Wednesday the communist North has reprocessed a small number of spent nuclear fuel rods, an important step in making weapons. The report came as North Korean envoys warned that the "black clouds of a nuclear war" are approaching.
The developments are likely to escalate the crisis over North Korea's suspected development of nuclear weapons.
South Korea's National Intelligence Service said in a report to the National Assembly that it believed North Korea has reprocessed "a small portion" of the 8,000 fuel rods at its nuclear facilities at Yongbyon.
Reprocessing all the rods could yield enough plutonium for several atomic bombs within months, adding to the North's suspected arsenal of one or two nuclear bombs, experts say.
Since April, North Korea has claimed that it had all but finished reprocessing the rods. Until now, both U.S. and South Korean officials have expressed doubt about the North Korean claim, speculating that it might be a bluff to extract concessions at the negotiating table.
South Korea receives much of its intelligence on North Korea from the United States, which uses satellites and surveillance aircraft to gather information.
Ko Young-koo, the intelligence service director, also said North Korea conducted nuclear-related tests of high explosives at Yongduk-dong, a site west of the Yongbyon nuclear complex. It was unclear whether the tests were recent. South Korea has been aware of similar tests over the past decade.
Also Wednesday, a high-level North Korean delegation used belligerent rhetoric on the first of four days of talks in Seoul between Cabinet-level delegations. The meetings are to promote inter-Korean projects, but South Korean officials plan to press North Korea to agree to multilateral talks on nuclear development.
"Our nation faces a stark situation as the black clouds of a nuclear war are coming toward the Korean Peninsula minute by minute," the North Koreans said in a reference to the nuclear dispute.
North Korea has used harsh language for decades, and U.S. and South Korean officials believe it's designed to escalate tension and gain concessions.
In an apparent reference to the U.S.-led victory in the Iraq war, the statement said "the aggressive forces are getting more frantic with war fevers as a result of a war in a different region."
But Kim Ryong Song, North Korea's chief delegate, said at a dinner banquet hosted by his South Korean counterpart, Unification Minister Jeong Se-hyun, that the two sides should work hard together despite the tense situation.
"At these talks, let's unite efforts and will, and reach an important agreement and give happiness and hope to our nation," he said.
Desperate for cash, North Korea is pursuing joint economic projects with wealthy South Korea, and often appeals for cross-border solidarity against the United States, the South's chief ally. The nuclear dispute has hindered progress on reconciliation between the two Koreas.
South Korean President Roh Moo-hyun is visiting China to enlist Beijing's help in peacefully resolving the nuclear standoff. China, which supports North Korea with food and fuel, has said it wants a Korean Peninsula free of nuclear weapons.
North Korea "has to choose the path of peace and coexistence with others," Roh said in Beijing on Wednesday. "No nation in the international community believes that the nuclear project will assure its future."
North Korea says it's willing to resolve U.S. security concerns if Washington provides security guarantees. The North is also desperate for economic aid.