WASHINGTON — An 18,000-page declaration submitted by North Korea to the U.S. is stirring debate about whether U.S. intelligence agencies previously overstated how much plutonium the Pyongyang government might have produced for its nuclear weapons program.

Bush administration officials have declined to comment on the declaration, which State Department officials say will take weeks to wade through, but they have indicated that North Korea is acknowledging it produced 37 kilograms of plutonium, or about 81 pounds.

That total would be more than the 30 kilograms, about 66 pounds, that North Korea has acknowledged previously, but somewhat less than the 40 kilograms to 50 kilograms (88 pounds to 110 pounds) that U.S. intelligence agencies had calculated in the past. Estimates on how many nuclear bombs North Korea could wring from its plutonium program have ranged from six to 10.

No one in the administration is prepared to accept the documents at face value, a Bush administration official said, and some intelligence analysts are particularly wary of the numbers they have seen so far. The official said that State Department negotiators were continuing to push the North to be as forthcoming as possible.

"We're coming to an important juncture in this process," Christopher R. Hill, the chief North Korea nuclear negotiator, told reporters in Moscow on Friday after meeting with his Russian counterpart and after meetings this week in Beijing with North Korean officials.

State Department officials have assembled a team of reactor experts and translators to review the seven boxes of documents in hand so far, and they say the process is slow going. The documents go back to 1987 and contain information about North Korea's three major campaigns to reprocess plutonium for nuclear weapons — in 1990, 2003 and 2005, administration officials said.

The documents do not include any information about North Korea's uranium program or the country's proliferation activities. The declaration is part of a so-called "six parties" nuclear agreement — still a work in progress — among North Korea, the United States, Russia, China, Japan and South Korea for the denuclearization of the Korean Peninsula.

Both the declaration and the agreement are facing skepticism from Congress and from more hard-line North Korea experts who say that the North cannot be trusted. A former U.S. diplomat who recently met with North Korea officials said Thursday at a forum on North Korea that the North was not planning to give up all its nuclear weapons or material when the agreement was completed.