The chief U.S. nuclear negotiator with North Korea will propose a face-saving compromise during a trip Wednesday to the isolated communist country to try to salvage the derailed disarmament pact, U.S. officials said.

Envoy Christopher Hill said his goal was to persuade North Korea's Deputy Foreign Minister Kim Kye Gwan to agree to Washington's demand for a verification system to account for the North's nuclear arsenal. But he acknowledged it would be a difficult task.

The North has rejected U.S. requests on verification and accused Washington of not living up to its end of the deal and removing North Korea from a list of state sponsors of terrorism. It recently reversed the process of dismantling its nuclear facilities.

"We are in a very difficult, very tough phase of negotiations," Hill told reporters Tuesday night after meeting with his South Korean counterpart, Kim Sook, to discuss ways to persuade the North to return to the disarmament process.

In Washington, a senior U.S. official said Hill is bringing a new face-saving proposal that would have North Korea agree to a verification program and submit it first to its Chinese allies. The official spoke on condition of anonymity because Hill has not presented the proposal.

The U.S. government would then provisionally remove North Korea from the terrorism sponsors list. That would edge around the current impasse, in which the United States says it won't remove North Korea from the list unless it first signs up to the verification measures.

U.S. officials said they were not sure North Korea will agree to the idea and if they do, whether what they present to the Chinese will be acceptable to Washington.

Hill's trip to the capital, Pyongyang, comes amid reports that North Korean leader Kim Jong Il suffered a stroke in August, prompting concern that his prolonged illness could destabilize the Korean peninsula. North Korea denies that Kim, 66, is ill.

Kim's disappearance from the public eye coincided with an about-face on the 2007 nuclear deal negotiated among six countries -- the two Koreas, the United States, China, Russia and Japan.

North Korea alarmed the world in 2006 by testing a nuclear device and a series of missiles, including one capable of reaching as far as Alaska. It then agreed to dismantle its nuclear program in exchange for energy aid and other concessions.

It began disabling its nuclear processing plant in Yongbyon in November, and blew up a cooling tower in June in a dramatic display of its determination to carry out the process.

Just steps away from completing the second phase of the three-part process, Pyongyang abruptly reversed course in mid-August and stopped disabling the plant.

After confirming it had begun restoring the nuclear reprocessing plant and testing an engine ignition, North Korea last week ordered UN nuclear inspectors to leave the country and said it planned to restart the plant. Experts say it could be up and running within months.

"What they have been doing obviously goes counter to the spirits of what we've trying to accomplish because all of the disablement -- shutdown and disablement -- was for the purpose of abandonment" of its nuclear program, Hill said.