North Korea's nuclear envoy said Thursday his country won't unilaterally abandon its atomic weapons program after two days of meetings with his U.S. counterpart failed to produce a date on restarting six-nation disarmament talks.

Later Thursday, Japan's envoy said the talks could still resume before the year's end. But speaking to reporters in Tokyo, Kenichiro Sasae -- Japan's representative to the talks -- said the timing for a new round would depend on what progress was made in preparatory talks.

"The possibility that talks could resume (in December) cannot be denied. So long as there is a forward-looking prospect we can hold talks anytime," Sasae said after talks with U.S. Assistant Secretary of State Christopher Hill, who was passing through Tokyo on his way home from Beijing where he met with his Chinese and North Korean counterparts.

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"We need to achieve results when we hold a next round of six-party talks," Sasae said.

The multination negotiations have been stalled for over a year due to a North Korean boycott, and efforts to resume the talks have gained greater impetus since the North tested a nuclear device on Oct. 9.

Earlier Thursday, North Korean Vice Foreign Minister Kim Kye Gwan said his country won't unilaterally abandon its atomic weapons program after two days of meetings with Hill in Beijing that failed to produce a date for restarting the talks.

But Kim, after meeting South Korea's main nuclear negotiator Chun Yung-woo on Thursday in the Chinese capital, also said Pyongyang still remains committed to an agreement made last year on the denuclearization of the Korean peninsula.

"Our denuclearization is the great leader's (Kim Il Sung's) 'dying instruction' and we are ready to implement our commitment in the Sept. 19 joint statement," Kim said, referring to the leader of North Korea from its founding in 1948 until his death in 1994, when he was succeeded by his son Kim Jong Il.

Kim added that his country "cannot unilaterally abandon" its atomic weapons program at this point.

Hill said he presented ideas to Kim on how the North Korean regime could disarm.

"These are ideas designed to make rapid progress," Hill told reporters before leaving Beijing. "We discussed them and they're taking them back to Pyongyang and we hope to hear from them soon."

He said dates for the next round of six-nation discussions were raised but gave no details. The China-hosted talks involve the United States, North Korea, Japan, South Korea and Russia, which did not send an envoy to Beijing for the informal talks.

Participants in the Beijing talks, however, did not set a deadline for North Korea to respond, Hill told reporters during his stopover in Tokyo.

"The purpose is that when we start the talks, that we really do make progress," Hill said. "The purpose of the six-party talks is not to talk, it's to achieve the denuclearization of the Korean peninsula."

Japanese Prime Minister Shinzo Abe echoed Hill's comments Thursday evening.

"The important thing is for North Korea to abandon its nuclear weapons, including existing plans. We have to make six-party talks the first step toward that goal," Abe told reporters.

North Korea's nuclear test has raised severe security concerns in Japan, and broader fears it could trigger a regional arms race.

On Thursday, Japanese Foreign Minister Taro Aso said his country has the technological know-how to produce a nuclear weapon, but no immediate plans to do so.

"Japan is capable of producing nuclear weapons," Aso told a parliamentary committee on security issues. "But we are not saying we have plans to possess nuclear weapons."

Aso, who has called for discussion of Japan's non-nuclear policy, also said Japan's pacifist constitution does not forbid possession of an atomic bomb for defense.

Japan's Kyodo News agency cited unidentified people at the Beijing talks as saying that Kim demanded that the U.S. lift financial sanctions and freeze U.N. sanctions that were imposed after the nuclear test.

Hill said the issue of Washington-imposed sanctions was discussed but he made it clear that denuclearization had to be addressed first.

"The best way for them to get out of sanctions is to get out of nuclear programs," he said. "Unless they denuclearize, nothing is going to be possible."

North Korea agreed in September 2005 to abandon its nuclear program in exchange for security guarantees and aid. But Washington imposed financial sanctions against a Macau-based bank on suspicions it was laundering counterfeit money for the North Koreans. Angered by the move, Pyongyang withdrew from the talks two months later.

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