Christopher Hill said he planned to continue talks with the North's negotiator Kim Kye-gwan again later Wednesday and possibly Thursday following an initial six-hour meeting Tuesday.

"When you have six hours of conversations and you're going to have some more... certainly you can characterize them as useful discussions," Hill told guests at an American Academy event in the German capital.

He declined to answer questions on the substance of the meeting but said he hoped the six-party talks, which collapsed in December in Beijing with no discernible progress, would start again "in January".

The Berlin meetings came ahead of Hill's visits beginning Friday to South Korea, China and Japan to continue consultations with key partners in the six-party talks on how to make progress in the next round of negotiations.

Hill, who was also to brief visiting US Secretary of State Condoleezza Rice on the meetings, noted that the Berlin talks were the first bilateral discussions he had held with Kim outside Beijing.

The two powers held landmark talks in Berlin in 1999 that ultimately led to the lifting of a half-century of restrictions on trade, travel and banking against North Korea after it agreed to a moratorium on missile tests.

But the crisis erupted again in 2002.

Six-party negotiations involving the United States, the two Koreas, Japan, Russia and China were suspended in late 2005 after North Korea walked out in protest at US financial sanctions imposed on a Macau bank accused of illicit dealings on behalf of Pyongyang.

The talks resumed in December last year -- following the North's October 9 nuclear weapons test -- and ended in deadlock as Pyongyang insisted the financial sanctions be lifted before it would discuss nuclear disarmament.

Russia on Wednesday called the US sanctions an obstacle to the resumption of talks and urged flexibility on both sides.

"The United States should have taken some steps toward the Koreans on lifting financial sanctions and discussing this question with them," Deputy Foreign Minister Alexander Losyukov, the head Russian negotiator on North Korea, was quoted as saying by state-run news agency RIA Novosti.

Losyukov also called on North Korea to reconsider its refusal to rejoin the negotiations on account of the US sanctions. "The link is not 100 percent justified," he was quoted as saying.

Hill declined to discuss the specifics of the latest negotiations but said that the sanctions over the Macau bank were "a separate process from the issue of denuclearization".

He said the other powers involved in the negotiations nevertheless had a raft of economic and diplomatic incentives to convince Pyongyang to abandon its nuclear weapons program.

"We have a lot of options for dealing with it but we don't have the option of walking away from it," he said.

"We'd really like to move this along as quickly as possible."

Japan and South Korea welcomed the Berlin talks and voiced hope for an early resumption of multilateral discussions on Pyongyang's nuclear arms program.

"Dialogue is a good thing," Japanese Chief Cabinet Secretary Yasuhisa Shiozaki, the top government spokesman, told reporters.

"The Berlin meeting should lay a good groundwork for an agreement on what initial steps to take to implement the September 19 statement," South Korea's foreign minister Song Min-Soon said, referring to a 2005 accord offering the North security and economic aid guarantees in return for disarmament.

Hill described that agreement as "a sort of bible for us" and said he hoped it would be the basis for a new agreement.

Despite Hill's relatively upbeat assessment, the former US ambassador to the UN, John Bolton, said the six-way talks had failed and a breakthrough would only come after Kim Jong-Il's regime ended.

"Six-party talks have not worked. They are not likely to work," he said.

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