Christopher Hill, right, the top U.S. nuclear negotiator, meets South Korean Unification Minister Chung Dong-young, left, in Seoul, before going to Beijing

Delegates have begun arriving in Beijing for the resumption Tuesday of six-nation talks on disarming North Korea's nuclear programs.

The Russian delegation was the first to arrive in Beijing Monday, with the chief envoy - Alexander Alexeyev - urging all parties to work together to reach a consensus that will lead to North Korea's nuclear disarmament.

It is the fifth time China, Japan, North Korea, Russia, South Korea, and the United States have gotten together in the past two years.

Talks among the six recessed last month with North Korea insisting it be allowed to have a non-military nuclear program to help fill its electricity demands. This new demand came only after South Korea promised to provide the North with all the power it needs in exchange for disarmament.

The United States has ruled out letting Pyongyang have any nuclear program because of concerns it could still make weapons. China and South Korea have very recently indicated they would be open to the idea, but only once current disarmament issues are resolved.

The reoccurring obstacle is over so-called sequencing.

"There was no serious discussion of the real issue that will determine whether denuclearization occurs, and that is the sequencing of steps by the two sides. That was the big issue last year, and it's the big issue," said Selig Harrison, an Asia expert at the U.S. policy institute of the Woodrow Wilson Center in Washington, D.C.

The sequencing crisis centers on demands by the United States and others for North Korea to first verifiably dismantle its nuclear programs - which violate international agreements. North Korea essentially wants massive aid and security guarantees before it gives up any nuclear ambition.

Four rounds of talks have produced nothing of substance. The modest aim of this week's meetings is to agree on a set of principles on which to base further negotiations.

Mutual distrust remains the key obstacle, and some analysts say that if this round of talks does produce a joint statement on a set of principles, it will be a very basic one.

"What it would boil down to is a set of common lowest denominators that would please nobody. It would essentially be a document that would essentially say nothing," said Toshi Yoshihara, a visiting professor at the U.S. Air War College in the United States who is an expert on East Asian security issues.

However, diplomats here say that even a set of basic principles would be a first step in moving the process along.

This round of open-ended talks is due to begin with a banquet late Tuesday. Formal negotiations are scheduled to start on Wednesday.