North Korean leader Kim Jong-il (C) inspects the Korean People's Army Unit 593 at an undisclosed location in North Korea in this photo released by the Korea Central News Agency on January 16, 2007. [Korea News Service/Reuters]

SEOUL, South Korea - North Korea said it reached an agreement with the US during this week's negotiations on its nuclear program, and the top US nuclear envoy expressed optimism Friday that progress could be made when wider arms talks reconvene.

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North Korea's Foreign Ministry said the three days of talks in Berlin between US envoy Christopher Hill and North Korea's main nuclear negotiator Kim Kye Gwan had been held "in a positive and sincere atmosphere and a certain agreement was reached there." No further details were given.

Hill said the talks laid the foundations for progress when six-nation nuclear negotiations talks resume and that he had agreed with his North Korean counterpart "on a number of issues." He declined to elaborate.

"I am pretty convinced that we have the basis for a good session of the six-party talks," he told reporters in Seoul after meeting South Korean Foreign Minister Song Min-soon and Seoul's nuclear envoy Chun Yung-woo. "I feel we are going to be able to make some progress."

"Essentially what we discussed was the way forward," Hill said.

The North also offered an upbeat assessment Friday.

"We paid attention to the direct dialogue held by the (North) and the US in a bid to settle knotty problems in resolving the nuclear issue," the North's ministry said Friday in a statement released by the country's official Korean Central News Agency.

On arriving in Seoul earlier Friday, Hill said he hoped the six-nation talks - which also include China, Japan and Russia - would meet again before the Lunar New Year holiday celebrated across Asia that falls this year on Feb. 18.

"It's up to the Chinese (hosts) but I would think we'll have a six-party meeting pretty soon," he said.

The last round in Beijing in December - held after the North conducted its first-ever nuclear test in October - ended without any breakthroughs.

The countries had been seeking to outline how to implement a September 2005 agreement where the North pledged to disarm in exchange for aid and security guarantees.

But North Korea refused to engage in any discussion of its arms program and repeated a demand for the US to lift its blacklisting of a Macau bank. The US had accused the bank of being complicit in the country's alleged counterfeiting and money laundering, leading the bank to freeze North Korean assets worth about US$24 million (euro18.3 million).

The US is holding separate financial talks with North Korea, but the last session that met alongside the nuclear talks in December made no progress.

Hill said a tentative date was set for the next financial talks but did not elaborate. He added that a location for the discussions had yet to be decided. The US had proposed the two sides meet in New York.

Hill was departing South Korea on Saturday for Tokyo and Beijing before returning to Washington.