BEIJING, Feb. 9 — North Korea and the United States appeared on Friday to be inching closer to a deal that would establish a schedule for the North to shut down and seal its main nuclear facilities within two months, in return for shipments of fuel oil from South Korea and the beginning of talks over normalization of relations with Washington.

<##IMAGE##> But the top American envoy negotiating the deal here cautioned that the two sides remained stuck on “one or two” small issues.

“Nothing is agreed unless everything is agreed,” the envoy, Christopher R. Hill, an assistant secretary of state, told reporters as he returned to his hotel Friday night. “So I just want to be careful about predicting success tomorrow.”

But in Washington, officials at the White House and the State Department were preparing for a major announcement this weekend, and described the agreement as very different from the nuclear freeze that the Clinton administration negotiated in 1994. That agreement ultimately fell apart, and the North has produced enough fuel for more than half a dozen nuclear weapons during President Bush"s term.

“This is the Libya model,” said one senior administration official, referring to Libya’s decision in late 2003 to turn over all of the equipment it had purchased from the secret nuclear network run by the Pakistani scientist, Abdul Qadeer Khan, to produce bomb fuel. In that agreement, both the Libyans and the United States executed a series of steps, in a carefully negotiated order, that rid the country of nuclear technology and ended its isolation.

It is still unclear exactly what sort of timeline North Korea would agree to, and how quickly it would turn over the plutonium it has produced, along with whatever weapons it may have built. In the past, the Bush administration has said it would never agree to the kind of “freeze” that President Clinton signed, because North Korea was not forced to give up its weapons fuel before it reaped rewards. That allowed the country to quickly restart its nuclear program, officials said.

Administration officials say this agreement would be different, because the biggest benefits for the North would come only after it allowed inspectors, sealed its facilities and began to give up its weapons. But those steps will be difficult to monitor, in part because there is a dispute about how much nuclear material the North possesses.

In a second stage of the agreement, the North would be required to declare how much nuclear material it has on hand and where it is located, administration officials say. Presumably, that would include the uranium enrichment program that Mr. Khan has admitted helping the North start a decade ago, but which North Korea has denied.

On Friday night, Mr. Hill insisted that North Korea would be required to do more than submit to a “freeze,” and also suggested that the process of shutting down the weapons program would be carried out in stages.

“We’re interested in shutting things down and continuing, through various phases, to shut down, dismantle, abandon things,” he said. “Freeze doesn’t describe that process. Freeze suggests a process where you freeze, you thaw out, freeze again. We’re not interested in that. We’re interested in kind of a one-way process.”

Mr. Hill said he remained “cautiously optimistic” and declined to specify which issues were delaying an agreement, though he suggested that North Korea had unexpectedly stalled on minor details. Negotiations resume Saturday, and Mr. Hill said he still hoped that a deal could be struck by the end of the weekend.

The latest negotiations over North Korea’s nuclear weapons program began Thursday in Beijing amid tempered optimism that a breakthrough, if a modest one, might be at hand. North Korea and the United States — the key players in talks that also include China, Japan, South Korea and Russia — held fruitful private meetings last month in Berlin.

Mr. Hill and his North Korean counterpart, Kim Kye-gwan, have met privately more than once this week, including for lunch on Friday. Mr. Kim has told reporters that North Korea is “ready to make its first step” toward denuclearization.

The starting point in the talks is a broad accord signed in September 2005, in which North Korea agreed in principle to end its nuclear weapons program in exchange for a package of economic and energy aid, as well as security guarantees.

Subsequent negotiations stalled over the contested details of how and when the accord would be carried out.

This week, though, a rough initial timeline has emerged. Russian, South Korean and Japanese news agencies have reported that a draft proposal circulated by China this week would require North Korea to stop operations at its nuclear reactors and procession facilities within two months in exchange for initial shipments of aid, including energy supplies such as heavy oil.

None of the negotiators have spoken publicly about the specifics of the proposal, but Mr. Hill confirmed that it would require “both sides” to take “initial actions” within weeks. Such a deal would constitute only a first phase of an overall denuclearization plan, and Mr. Hill suggested that more rounds of negotiations could be held in March and April.

The paramount goal of the talks is eliminating North Korea’s nuclear weapons program, but the negotiations have been complicated by a host of related issues.

Mr. Hill said the proposed draft would also create five working groups to negotiate separate issues. Analysts say these are likely to include denuclearization, financial sanctions and normalizing diplomatic relations between North Korea and the United States and Japan.

The United States infuriated the North Koreans when it froze $24 million of their country’s assets and accused them of laundering counterfeit dollars. North Korea has demanded that the money be released, and financial negotiators from both countries met last week in Beijing. No deal was announced, and some analysts have questioned whether a stalemate could sink a larger denuclearization deal.

But Mr. Hill said the money dispute was not one of the sticking points holding up the current deal. “When I talk about one or two issues,” he said of the unresolved problems, “that is not one of them.”

Jim Yardley reported from Beijing, and David E. Sanger from Washington.