A senior US envoy has described talks with North Korea as "very useful," following a three-day trip to the communist country.
Envoy Stephen Bosworth made the remark at an airport in Pyongyang as he headed to South Korea after his visit, according to China's Xinhua news agency. "It was a very useful set of meetings," he was quoted as saying.
Still, it was unclear if his comment means success in his mission to win North Korea's commitment to return to international nuclear negotiations. Pyongyang walked away from the talks earlier this year, angered by criticism of its nuclear and missile programs. A nuclear test soon followed.
Pyongyang's official Korean Central News Agency said in a one-sentence dispatch that Bosworth's delegation had left.
Bosworth and Washington's chief nuclear negotiator, Sung Kim, smiled lightly while shaking hands with North Korean officials at the airport before getting on a bus and then onto their plane, footage from broadcaster APTN in North Korea showed.
He landed at a US military base near Seoul, Xinhua and South Korea's Yonhap news agency said. He was scheduled to brief US and South Korean officials on the visit.
In Washington, State Department spokesman Ian Kelly said he had no information on how the talks went or who the envoy met. "I think that there will be a lot more information flowing once he hits the ground in Seoul," he said.
Bosworth's three-day visit to Pyongyang is the first by a US official since President Barack Obama took office.
There had been speculation that North Korea would demand that the US sign a peace treaty with it in return for rejoining the six-party talks, which involve the two Koreas, China, Russia, Japan and the US.
The two Koreas have been locked in a truce, without a peace treaty, since the close of the 1950-53 Korean War. Wary of the 28,500 troops Washington has stationed in South Korea, North Korea has long sought a peace treaty with the US.
North Korea says the lack of a treaty is evidence that the US bears a "hostile" attitude toward Pyongyang, and that the regime needs to develop atomic bombs to defend itself in case the US attacks.
US officials say a peace treaty was not on the agenda for Bosworth's trip to North Korea. However, State Department spokesman P.J. Crowley said Tuesday that it "would not surprise us" if the North raised other issues.
"We will make clear to them that should they return to the six-party process and should they reaffirm their commitments" under a 2005 disarmament pact, then an avenue for bilateral talks will be available to them, he said.
AP