North Korea (search) said Tuesday it would not dismantle its nuclear weapons program until the United States first provides an atomic energy reactor, casting doubt on its commitment to a breakthrough agreement reached at international arms talks.

The North insisted during arms talks that began last week in Beijing (search) that it be given a light-water reactor, a type less easily diverted for weapons use, in exchange for abandoning nuclear weapons. The agreement reached at the talks' end Monday — the first since the negotiations began in August 2003 — says the six countries in the negotiations will discuss the reactor issue "at an appropriate time."

Both the United States and Japan, members of the six-nation disarmament talks, rejected the North's latest demand.

"This is not the agreement that they signed and we'll give them some time to reflect," State Department spokesman Sean McCormack (search) said.

Japanese Foreign Minister Nobutaka Machimura (search) called the reactor demand "unacceptable."

The Beijing agreement called for the North to abandon it arms efforts and accept inspections by the International Atomic Energy Agency (search) in exchange for energy, economic and security aid.

But the North's statement Tuesday indicated it was again raising the reactor demand as a prerequisite for disarming.

"We will return to the NPT and sign the safeguards agreement with the IAEA and comply with it immediately upon the U.S. provision of LWRs, a basis of confidence-building to us," the North's Foreign Ministry said in the statement, carried by the North's official Korean Central News Agency.

"The U.S. should not even dream of the issue of (North Korea's) dismantlement of its nuclear deterrent before providing LWRs," the North said.

The impact of the North's statement wasn't immediately clear. During the years of debate over its weapons program, the communist nation has sometimes given confusing or dramatic statements as it publicly maneuvers for negotiating leverage.

Other countries at the talks made clear that the reactor could only be discussed after the North rejoins the Nuclear Nonproliferation Treaty (search) and accepts inspections from the International Atomic Energy Agency — which North Korea pledged to do in Monday's agreement.

U.S. State Department spokesman Adam Ereli emphasized earlier in Washington that the "appropriate time" for discussing the reactor means only after the North comes in compliance with those conditions.

"It's a theoretical proposition in the future, contingent on dismantling having taken place, resigning up to the NPT and having IAEA safeguards in place," he said Monday in Washington.

The North's position is likely to be a major sticking point in talks slated to begin in early November on implementing Monday's agreement.

The North had demanded during the six-nation talks in Beijing — which include China, Japan, Russia, the United States and the two Koreas — that it be allowed to keep a civilian nuclear program for power generation after it disarms.

But the United States strongly opposed the demand, and Monday's agreement only acknowledged that the North had "stated" its claim to that right.

The administration of U.S. President George W. Bush (search) has opposed anything resembling a 1994 U.S.-North Korea agreement, which promised the North two light-water reactors for power. That project stalled amid the current crisis that broke out in late 2002 over the North's resumed nuclear weapons program.