After a second day of talks on North Korea's nuclear-weapons programs, North Korea and the United States are still far apart on how to achieve Pyongyang's disarmament.   Diplomats say the problem is to agree on who gives what, and when.

Diplomats at the six-party talks in Beijing say one of the major points of dispute between Washington and Pyongyang is what they call "sequencing," deciding which side will make concessions first, and in what order those concessions should come.

During the second day of talks, North Korea reportedly reiterated demands that the United States remove nuclear weapons from the Korean Peninsula, normalize relations with North Korea and give security guarantees to the communist state.

Only at that point, the North Koreans say, will they give up their nuclear-weapons programs.

That is the opposite of Washington's view of how the disarmament should be carried out.  The Bush Administration wants North Korea to permanently and verifiably dismantle its nuclear weapons programs prior to Washington's making concessions.  Washington and Seoul also deny that there are any nuclear weapons in South Korea.

U.S. delegation leader Christopher Hill said North Korea has made its concerns over the "sequencing" of events known.

"They do not want to have obligations ahead of other people's obligations," said Mr. Hill.

The talks, which also involve China, Japan, South Korea and Russia, resumed Tuesday after a 13-month boycott by North Korea.

A senior official says the U.S. delegation had a "good exchange of views" with the North Koreans since Tuesday's opening, but that "fundamental differences" remain.

The official said all sides are still trying to reach a consensus on the concept of "denuclearization", saying the North Koreans have a broader view of the issue, which could touch on the U.S.-South Korean defense alliance.

Host China has been urging all six nations participating in the talks to adopt flexible and practical attitudes in order to resolve the issue.  Chinese Vice Foreign Minister Wu Dawei Wednesday called for all participants to use their "utmost political courage" to achieve progress.

Ralph Cossa, a North Korea expert with the U.S.-based Center for Strategic and International Studies, says real progress in the talks is still anything but a certainty.

"I would expect the North Koreans would now be prepared to put something on the table. The question is whether or not they will make a quote strategic decision, unquote, to commit to ending their nuclear weapons programs, or whether they'll throw [in] pre-conditions," said Mr. Cossa.

Diplomats in Beijing do not expect a final settlement in this fourth round of talks, and no end date for the talks has been set yet, in order to maximize the chance of progress.