Seoul, South Korea A defiant North Korea ordered U.N. nuclear inspectors to leave the country and said Friday it would restart a laboratory capable of producing plutonium for nuclear weapons. But the U.N. nuclear watchdog said its inspectors were "staying put" for now.
A White House spokesman denounced the expulsions and called on Pyongyang to shut down its nuclear weapons program. U.S. officials said an envoy -- possibly Assistant Secretary of State James Kelly -- likely would visit the region next month to confer with allies.
But there was no indication that Washington would talk with North Korea.
"We will not respond to threats or broken commitments," White House spokesman Scott McClellan said from Crawford, Tex.
The Vienna-based International Atomic Energy Agency said Friday that it received a letter from North Korea "requesting the immediate removal of IAEA inspectors" from the nuclear complex at Yongbyon, 50 miles north of the capital, Pyongyang.
There was no word on when the North wanted the inspectors out, although IAEA spokeswoman Melissa Fleming said inspectors "are staying put" and "are on standby."
North Korea also said it planned to reactivate a Yongbyon reprocessing laboratory to store spent fuel rods from nuclear reactors, which would generate badly needed electricity for the impoverished nation.
North Korea has one 5-megawatt reactor, and said it planned to resume building two larger, unfinished ones. The North declared Dec. 12 it would restart the 5-megawatt reactor, but IAEA and U.S. officials say the reactor can generate only negligible amounts of power.
The laboratory can extract plutonium, a component of atomic bombs, from used fuel rods. North Korea already holds 8,000 spent fuel rods, which U.S. officials say contain enough plutonium to make several atomic bombs.
Pyongyang said in its letter, a copy of which was obtained by The Associated Press, that it decided to reactivate the complex after the United States canceled a fuel oil shipment promised in a 1994 agreement shutting down the facilities.
Those shipments were halted after it was revealed that North Korea was covertly developing nuclear weapons in violation of the 1994 agreement.
The most immediate fear of the IAEA is that North Korea could begin a weapons-making process that experts believe could yield several bombs within months.
"Together with the loss of cameras and seals, the departure of inspectors would practically bring an end to our ability to monitor (North Korea's) nuclear program or assess its nature," IAEA director Mohamed ElBaradei said. "This is one further step away from defusing the crisis."
North Korea could take other steps to heighten the conflict, including withdrawing from the international Treaty on the Non-Proliferation of Nuclear Weapons. In 1993, it announced its withdrawal from the treaty, though it later suspended the decision.
South Korea said Saturday that it was sending special envoys to Russia and China "at the earliest possible date" to seek help in resolving the dispute.
"We consider all possibilities but for now our focus is on dissuading the North from restarting the radiochemical lab," a senior Foreign Ministry official, requesting anonymity, said at a briefing to local reporters.
South Korea, the official said, also is pushing to hold a high-level three-way meeting with the United States and Japan early next year.
The developments renewed fears that the Korean Peninsula was spiraling into a nuclear crisis similar to one in 1994, during which the U.S. military devised plans to bomb the Yongbyon site.
Huge armies, including 37,000 U.S. soldiers in the South, face each other across a border laced with fences, tank traps and mines.