The State Department said Tuesday the complete dismantling of North Korea's nuclear program remains the goal of the Chinese-led six-party negotiations with Pyongyang. The comment followed an assertion by a leading U.S. academic that North Korea appears determined to retain a small arsenal of nuclear weapons.

The State Department says while the Obama administration is reviewing all aspects of U.S. policy toward North Korea, it has not changed the ultimate objective of achieving a nuclear free Korean Peninsula.

The comments here came in response to a published assertion by U.S. Asia scholar Selig Harrison that North Korea appears adamant in holding on to the small arsenal of nuclear weapons it is understood to have produced in recent years, and is unlikely to be willing to negotiate anything other than a cap on its weapons holdings.

Harrison, a former Washington Post Asia correspondent and now a scholar with the Washington-based Center for International Policy, said in a Washington Post column Tuesday that he visited North Korea last month and found a hardening of policy there - apparently related to the reported illness of the country's leader, Kim Jong Il.

Harrison said he was told by North Korean officials the communist state was ready to rule out building additional weapons, but that relinquishing already-weaponized nuclear material would depend on how Pyongyang's relationship with Washington evolved - a seeming roll-back from its 2005 agreement-in-principle to disarm in return for various benefits.

At a news briefing, State Department Deputy Spokesman Gordon Duguid said the desired "end state" of the six-party negotiations continues to be a nuclear-free Korea.

"Any move to change the six-party process, or not to live up to the commitments to the six-party talks, of course would be of concern," he said. "However, the North Koreans have agreed,  have made commitments to the international community and particularly to the members of the six-party talks, to carry our certain functions, certain activities that will provide the actions-for-action moves that we will take. So they should focus on those commitments that they have made rather than statements that are not particularly helpful."

North Korea agreed in principle to ultimately scrap its nuclear program including weapons in return for energy aid and diplomatic benefits from the other parties to the Chinese-led talks, which include South Korea, Japan and Russia in addition to North Korea, the United States and host China..

The negotiations have been stalled for several months over Pyongyang's refusal to accept a verification plan for the declaration of its nuclear assets and activities it made last June.

The nuclear talks have been a key issue in Secretary of State Hillary Clinton's visit to Japan, which ends Wednesday. She has said in Tokyo the United States expects North Korea to fulfill its obligations, and that reported plans by Pyongyang to test a long-range missile would be "very unhelpful."

Asia scholar Harrison said in his commentary Tuesday that the hard-line stance he encountered in Pyongyang suggests the United States might have to accept the idea of a nuclear North Korea and formulate policy accordingly.

A senior official here said while Harrison is a private citizen, North Korea has used him as a conduit for relaying official views before and that he expects him to be in touch with State Department officials on his latest trip.