Secretary of State Colin Powell spent a fourth straight day talking to North Korea's neighbors about a growing nuclear crisis as Pyongyang warned of "an uncontrollable catastrophe" if Washington maintains a hostile policy.
Powell spoke Tuesday to Japanese Foreign Minister Yoriko Kawaguchi. Since Saturday he has also spoken with the leaders of Russia, China, South Korea, Britain and France.
The White House sought to project an air of calm as North Korea issued its strongest statement since it moved last weekend to restart a nuclear reactor that U.S. officials say is a step toward building new atomic weapons.
President Bush was monitoring developments on North Korea from Camp David, where he was spending a long Christmas holiday with his family, said spokesman Scott Stanzel.
The North's defense minister, Kim Il Chol, said in a separate KCNA report that "U.S. hawks" were escalating the situation to "an extremely dangerous phase."
North Korea said Washington's hostile policy toward it would backfire and result in "an uncontrollable catastrophe." The statement by the North's communist party organ, Rodong Sinmun, was carried by the foreign news outlet Korean Central News Agency.
White House spokesman Sean McCormack had no direct comment on the new warnings from North Korea.
"We've made very clear we want a peaceful resolution to the situation North Korea has created by pursuing a covert nuclear weapons program, and as the president has said before, we have no intention of invading North Korea," he said.
A South Korean Foreign Ministry official said North Korean technicians had removed U.N. seals and cameras from a fourth nuclear facility, a plant that makes fuel rods. The only nuclear facilities that remain untouched are two unfinished reactors.
Over the weekend, North Korea began removing the U.N. seals and surveillance cameras from three Soviet-designed nuclear facilities that could yield weapons within months.
The United States could make war against North Korea even during a conflict with Iraq, Defense Secretary Donald H. Rumsfeld said Monday. But he said diplomacy, not the threat of military action, guides the Bush administration's efforts to contain Pyongyang's resurgent nuclear ambitions.
The administration demanded Monday that North Korea halt plans to restart a dormant nuclear reactor that was critical to that country's nuclear weapons program.
It pressed the communist government in Pyongyang to restore U.N. surveillance gear that it dismantled at a nuclear reactor at Yongbyon and not to restart the facility.
North Korea said the reactor will be used to generate electricity, an assertion Washington rejected.
Rumsfeld said North Korea should not take the current focus on Iraq as tacit approval to go forward with its weapons programs.
"We are capable of fighting two major regional conflicts," Rumsfeld said. "We're capable of winning decisively in one and swiftly defeating in the case of the other, and let there be no doubt about it."
Rumsfeld said no military action was imminent to halt Pyongyang's nuclear efforts, and White House officials said the United States intends to pursue a diplomatic course to persuade North Korea to abandon efforts to expand its nuclear arsenal.
A senior administration official said Monday the United States does not believe the North Koreans have opened the canisters containing the fuel rods. There were conflicting reports on that question Tuesday, and the American officials could not immediately say whether North Korea was removing the rods.
International Atomic Energy Agency spokesman Mark Gwozdecky said the U.N. agency cannot confirm that North Korea has begun removing nuclear fuel rods.
If rods were indeed removed, they could have been either spent fuel rods or fresh fuel rods.
"In the case of spent fuel rods, the intention could be to reprocess them to make plutonium," he said. "And they (the North Koreans) have no legitimate civilian use for plutonium."
Fresh fuel rods, instead, could be loaded into a reactor to produce electricity.
North Korea said Monday the nuclear issue could be settled if Washington were to sign a nonaggression treaty.
But the United States, angry because North Korea resumed its nuclear efforts despite a 1994 agreement to abandon it, sees little reason to negotiate.
"We will not give in to blackmail," State Department spokesman Philip Reeker said Monday. "We're not going to bargain or offer inducements for North Korea to live up to the treaties and agreements that it has signed."
Rep. Curt Weldon, R-Pa., a senior Armed Services Committee member, said he is seeking visas to lead a congressional delegation to the North Korean capital for talks. "When you don't have dialogue, that is when the problems develop, and that's my concern with North Korea," Weldon said.
Asked whether the U.S. military has drawn up plans to make war on North Korea, Rumsfeld said, "One of the assignments of the department is to prepare for a whole host of contingencies. We tend not to get into details as to what those contingencies might be."
The Clinton administration considered bombing the Yongbyon site in 1994 before North Korea agreed to shut it down. Under the 1994 agreement, North Korea pledged to freeze and eventually dismantle its nuclear weapons program in exchange for international aid to build two power-producing nuclear reactors.
Scheduled for completion by 2003, the light-water reactors are far behind schedule.
U.S. intelligence officials believe North Korea made one or two nuclear weapons in the 1990s with plutonium. They also are concerned that Kim's government could provide nuclear materials and expertise to other nations unfriendly to the United States.
The Associated Press contributed to this report.