A senior North Korean diplomat headed to the United States on Tuesday for rare talks with U.S. officials, a diplomatic source in Seoul said, amid cautious hopes for the resumption of stalled six-party talks on ending the North's nuclear programs.

Kim Kye-gwan, the North's first vice foreign minister and one of the key strategists in Pyongyang's nuclear talks with Washington, left Beijing on Tuesday morning and was due to arrive in New York for meetings with U.S. diplomats, the source said on the condition of anonymity.

Kim was scheduled to meet with Stephen Bosworth, Washington's top envoy on North Korea, during his visit, according to the source.

The U.S. visit was his first since March 2007 and his meeting with Bosworth is also his first since December 2009, when the senior U.S. diplomat visited Pyongyang.

Kim's visit to the U.S. comes days after the nuclear envoys of South Korea and North Korea met on the sidelines of an Asian security conference in Bali last week and agreed to make joint efforts to swiftly resume the six-party talks.

The surprise meeting between Wi Sung-lac of South Korea and his newly appointed North Korean counterpart, Ri Yong-ho, provided a ray of hope for the future of the deadlocked six-party talks that also involve the U.S., China, Japan and Russia.

Efforts to reopen the six-party talks, dormant since December 2008, have been complicated by the North's deadly military attacks on the South last year and its self-confessed uranium enrichment program.

Cho Byung-jae, spokesman for South Korea's Foreign Ministry, told reporters that Kim and U.S. officials were "expected to discuss a wide range of issues on the North's denuclearization process and U.S.-North Korea relations."

"With the inter-Korean dialogue on denuclearization, various bilateral and multilateral contacts become possible," Cho said. "In this context, the U.S.-North Korea contact can be interpreted as the beginning of another step."

But, the spokesman noted, North Korea must take responsibility for its military attacks on the South last year -- the sinking of the Cheonan warship and the shelling of Yeonpyeong Island. The attacks killed a total of 50 South Koreans, including two civilians.

"As for the Cheonan warship and Yeonpyeong Island issues, those incidents were the North's provocations that led to clear losses of our nationals' lives and property," Cho said.

"Therefore we believe that glossing over the issues is something unacceptable given the public's feelings and sentiments,"

he said. "So, I think the issues could pose a significant impact on the process of the six-party talks."

The inter-Korean dialogue in Bali was the fulfillment of the first of a three-stage approach being promoted by South Korea and its allies to reopen the six-party forum. The approach also calls for a direct U.S.-North Korea dialogue.

U.S. Secretary of State Hillary Clinton said Sunday that the North's first vice foreign minister Kim would visit New York this week for "exploratory talks" on potential resumption of stalled six-party negotiations. (Yonhap News)