CAMP DAVID -- President Bush dismissed assertions yesterday that his administration had softened demands that North Korea fully declare all of its nuclear activities, including secret efforts to enrich uranium and sell nuclear technology abroad.
Appearing at the presidential retreat with South Korea's new president, Lee Myung Bak, Bush said that any judgment about North Korea's willingness to dismantle its nuclear program - the core of an agreement negotiated last year - would only come once North Korea completed a declaration of its nuclear activities.
The deadline for that declaration passed at the end of last year, and no new deadline has been set.
That has left the agreement, signed 14 months ago by North and South Korea, the United States, China, Japan and Russia, increasingly in doubt.
Bush, facing criticism from some conservatives, distanced himself from statements by administration officials that the United States and other countries were prepared to accept something less than a full admission about North Korea's secret nuclear programs.
"Look, we're going to make a judgment as to whether North Korea has met its obligations to account for its nuclear program and activities, as well as meet its obligations to disable its reactor," Bush said, referring to North Korea's known plutonium reactor in Yongbyon. "In other words, we'll see. The burden of proof is theirs."
Lee, a conservative who was elected in December, echoed Bush's position.
He insisted that "under no circumstances" would North Korea be allowed to retain possession of nuclear weapons.
He also urged patience, though, saying that a negotiated settlement remained the best option to dismantle the North Korean nuclear arsenal.
North Korea tested a nuclear bomb in 2006 and is estimated to have enough material to assemble several more weapons.
Neither Lee nor Bush indicated how long they would be willing to give North Korea to make its declaration.
"It's difficult to convince North Korea to give up its nuclear weapons," Lee said, speaking through a translator, "but it is not impossible."