N. Korea Threatens South Over Nukes

SEOUL, South Korea - — SEOUL, South Korea - -North Korea lashed out at the United States and South Korea on Wednesday, warning that it would attack the South if any of its ships were intercepted as part of a U.S.-led initiative to stem the world trade in nuclear weapons.

North Korea's state-run news service reiterated the North's anger over South Korea's decision to join 100 other nations in the so-called Proliferation Security Initiative to blockade any nation suspected of trading nuclear materials.

The developments came amid reports that North Korea had staged mass rallies to celebrate its second nuclear test, an event Monday that has brought condemnation elsewhere.

The North Korean news service, which is often used by leader Kim Jong Il to express policy statements, added that it considered South Korea's move to join PSI a "declaration of war."

In Washington, the White House dismissed the threats as "bluster."

Meanwhile, experts were looking Wednesday for signs that North Korea might have begun reprocessing spent nuclear fuel rods to harvest weapons-grade plutonium. The move followed a Seoul newspaper report that U.S. spy satellites detected steam coming from the nuclear facility in Yongbyon.