| KYOTO, Japan
KYOTO, Japan The United States believes it has the means to verify North Korea's estimate of its nuclear programmes, U.S. Secretary of State Condoleezza Rice said on Thursday.
North Korea was expected to declare between 30-50 kg (66-110 lb) of plutonium in the document, given to the Chinese government on Thursday, a senior U.S. administration official said separately, but added that "our estimates are greater".
Verification, which meant calculating and resolving differences in estimates, could take "months and months" he said.
"We believe we have ... the means by which to verify the completeness and accuracy of this document," Rice told reporters in Kyoto, Japan, where she is attending a meeting of foreign ministers from the Group of Eight (G8) countries.
"For instance, in order to verify the plutonium number that the North Koreans have given, we have been given documents, but we also are expecting access to the reactor core, to the waste pool," she said, referring to North Korea's nuclear reactor at Yongbyon.
Neither Rice, nor the senior official who also spoke to reporters in Kyoto, have seen the declaration, which is some 60 pages long, but expect to get it shortly.
"This is an important first step, but a first step reward denuclearisation, which means a verifiable end to all North Korea's nuclear programmes," Rice said.
The senior official said efforts were being made to set up a meeting soon of the lead negotiators in the six-party talks that led to the agreement requiring North Korea to produce its nuclear accounting. Those countries are the two Koreas, China, Russia, Japan and the United States.
He did not think the meeting could happen before Monday in Beijing, which as the host of the six-party process received the declaration from Pyongyang on Thursday.
For the negotiators, "the most urgent task is to get together and take the agreement, on principles, and turn that into a verification agreement, or protocol of some kind," the official said.
The declaration was actually a package, the official said. North Korea's disclosure of its plutonium programme was handed over on Thursday, but Pyongyang had already submitted a much shorter document -- of perhaps two pages -- on uranium enrichment and proliferation activities.
"It's our expression of concern, and an expression from the North Koreans that they acknowledge our concerns" on those matters, the senior official said.
Washington has accused Pyongyang of pursuing a uranium enrichment programme, which could provide it with a second way to produce material for nuclear weapons in addition to the plutonium-based programme used in North Korea's 2006 nuclear test.
The United States has also accused North Korea of helping Syria with a suspected nuclear reactor project that Israel destroyed in a September air strike.
North Korea has agreed to "deal with" the U.S.'s uranium enrichment concerns, the official said without elaborating. As for proliferation: "They have said they don't have any proliferation now, which by the way we would agree with."
The goal of the six-party process, the official said, was for North Korea to hand over its plutonium and any nuclear weapons, which was supposed to happen in the next phase after verification.
He thought Pyongyang wanted to postpone the weapons handover, adding: "We don't even know to what extent they have weapons."
(Reporting by Susan Cornwell, editing by Rodney Joyce)