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The United States could fight North Korea even during a war with Iraq, Defense Secretary Donald Rumsfeld warned Tuesday.

But he said diplomacy, not the threat of military action, guides the Bush administration's efforts to contain Pyongyang's resurgent nuclear ambitions.

The Bush administration demanded on 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.

Rumsfeld said at a Pentagon news conference that 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.

Discussions on the North Korean question are under way with China, Russia and other countries, the State Department said.

North Korea has said it needs the power the reactor would produce, but officials said the reactor would provide negligible electricity to the country's grid. Instead, U.S. officials accused Pyongyang of planning to restart the facility to support weapons programs.

The Vienna-based International Atomic Energy Agency, a U.N. monitoring agency, said Pyongyang unsealed a storage chamber at Yongbyon this weekend that holds 8,000 irradiated fuel rods. Plutonium in the rods could yield four or five nuclear weapons within months, experts say.

A senior administration official said the United States does not believe the North Koreans have opened the canisters containing the fuel rods.

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.

Supposed to have been completed by 2003, the light-water reactors are far behind schedule.

"The situation today is somewhat different from then," Rumsfeld said, without elaborating.

Relations between the countries have deteriorated rapidly since President Bush took office. Shortly afterward, Bush suspended contacts between the governments and ordered a full review of relations. In his 2001 State of the Union address, he placed North Korea in an "axis of evil" with Iran and Iraq.

Rumsfeld rejected the notion that Bush administration statements had forced North Korea to renew its nuclear efforts, saying the United States now believes Pyongyang has had a clandestine nuclear program for years.

"Do you think the idea that it's the rhetoric from the United States that's causing them to starve their people or to do these idiotic things or try to build a nuclear power plant?" he asked.

Rumsfeld also accused North Korea of operating concentration camps. Human rights groups say the camps hold political prisoners.

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.

Nuclear weapons also can be made with enriched uranium, and on Oct. 4, North Korea admitted to American diplomats having a program to enrich uranium to weapons grade.

In response, Bush halted oil shipments the United States had provided the energy-poor country under the Clinton-era agreement. The North Koreans then said they would restart nuclear energy facilities shut down as part of the pact.

The Associated Press contributed to this report.