BEIJING – North Korea has relied on its trademark brinksmanship strategy in international negotiations on its nuclear program, often lacing its speeches with threats, accusations and unreasonable demands.

But no more _ at least at the latest round.

The communist nation has been unprecedentedly cooperative, U.S. and South Korean nuclear envoys have said this week in Beijing, raising hopes about charting its future disarmament course following the shutdown of its main nuclear reactor a week ago.

U.S. chief nuclear envoy Christopher Hill repeatedly praised his counterpart from Pyongyang, Kim Kye Gwan, for his “businesslike” attitude and for not raising any irrelevant issues or demands that could scuttle the talks.

“Of all the six-party meetings I’ve gone to, this was for me the best meeting because everyone was very much focused on the task ahead, very little polemics, very little wandering off into other areas,” Hill said Thursday.

South Korean envoy Chun Yung-woo _ apparently impressed by the North’s changed attitude _ also said the atmosphere when the talks opened Wednesday was “as bright as Beijing’s skies.”

The North’s attitude gave rise to hope that this week’s talks could yield a further breakthrough: setting a year-end deadline for the North to declare its nuclear programs and disable related facilities.

That did not materialize, and the talks ended with envoys promising to meet again.

Still, Hill and Chun stuck to their view that the talks were a success.

“North Korea said it would not drag its feet in moving on to the next phase and would declare everything it has. In that sense, there has been considerable achievement,” Chun said after the end of the talks.

“With a little luck, we can wrap this up by the end of the year,” Hill said before departing Beijing. “It’s going to be difficult, but we’ll do our best.”

The six-nation talks _ launched in 2003 among China, Japan, the two Koreas, Russia and the United States _ have often opened on a downbeat note, as North Korea’s keynote speeches at opening sessions were laced with anti-U.S. rhetoric, threats to increase what it dubs its “nuclear deterrent” or unacceptable demands.

Even when the forum produced its first-ever agreement in September 2005, North Korea quickly turned the much-hailed deal sour a day later by claiming it would not carry it out unless it first gets nuclear reactors for generating power.

That demand was unacceptable to the others, because the deal called only for discussions on such facilities at an appropriate time.

Tensions later rose because of a separate banking dispute between the North and the United States, and Pyongyang conducted its first nuclear test last October.

The North’s defiant antics are the main fodder for critics who say the regime is untrustworthy and has no intention of giving up its nuclear ambitions.

It is unclear what has made North Korea change its attitude, or if that change is a sign that the communist nation is now serious about giving up its hard-won nuclear weapons and facilities.

But one possibility is that a tiny bit of trust has developed between Washington and Pyongyang, Cold War foes which fought each other during the 1950-53 Korean War and remain technically at war.

The better ties were kindled with surprise one-on-one meetings between Hill and Kim in Berlin for several days in January.

Those meetings helped produce a breakthrough in the prolonged banking dispute that had held up the nuclear disarmament talks.

It took a few more months to resolve the row over some $25 million in North Korean funds in a U.S.-blacklisted Macau bank, because of legal and technical problems.

However, Washington recently has made efforts to settle the dispute and authorized Hill to make a surprise trip to Pyongyang last month. Those goodwill gestures may have made North Korea do away with some of its mistrust of the United States.

It remains to be seen whether Pyongyang now trusts Washington enough to give up its nuclear weapons and programs _ or if its newfound sweet-talk is merely part of a broader strategy to stall for time to extract yet more concessions.

Associated Press reporter Jae-soon Chang, based in Seoul, has covered the North Korea nuclear standoff since 2002.

A service of the Associated Press(AP)