By Stephanie Nebehay
GENEVA (Reuters) - The United States ended two days of meetings with North Korea on Tuesday sounding upbeat about an eventual return to wider talks on ending Pyongyang's atomic programs but saying there was no immediate breakthrough.
Meeting for the second time in three months, the United States and the North appear to be inching toward a resumption of six-party talks, which aimed to wean North Korea of its nuclear programs but collapsed in December 2008.
The meetings, as well as earlier talks between North and South Korea, appear to mark the end of a period of acute tensions last year when Seoul accused Pyongyang of sinking one of its ships and shelling one of its islands.
Ambassador Stephen Bosworth, U.S. special representative for North Korea policy, said differences between Washington and Pyongyang had been narrowed but did not offer details.
"It has been a very useful meeting," Bosworth told reporters outside the U.S. diplomatic mission in Geneva after his talks with North Korean First Vice Foreign Minister Kim Kye-gwan. "The tone was positive and generally constructive."
"I am confident that with continued effort on both sides we can reach a reasonable basis of departure for formal negotiations for a return to the six-party process," he added.
Bosworth said the discussions "touched on all issues," including humanitarian aid, but declined to say whether North Korea's contested uranium enrichment program was the focus.
In addition to its plutonium-based nuclear program, which was the basis for its 2006 and 2009 nuclear tests, North Korea has a uranium enrichment program which could provide it with a second path to produce nuclear weapons.
"We narrowed differences on several points and explored our differences on other points. We came to the conclusion that we will need more time and more discussion to reach agreement," Bosworth said, saying the two sides had a long history marked by "many differences," not all of which can be overcome soon.
In the cautious world of U.S.-North Korean diplomacy, his comments were relatively upbeat. But U.S. State Department spokeswoman Victoria Nuland told reporters in Washington that, "while there's been some narrowing of differences, we haven't had any breakthroughs here and significant issues do remain."
Kim, North Korea's lead nuclear negotiator, said the talks touched on how to build confidence.
"Based on our previous talks, we held intensive discussions on ways to build trust in North Korea-U.S. relations," the North Korean official told reporters.
The two sides held bilateral talks in New York in late July, the first since six-party talks over Pyongyang's nuclear weapons program collapsed. The wider talks include South Korea, China, Japan and Russia.
The United States and South Korea insist that the North immediately halt its uranium enrichment work, which it unveiled last year, as a precursor to restarting regional talks that offer aid in return for denuclearization by Pyongyang.
U.S. and North Korean officials will now consult with their respective capitals and stay in touch via the New York diplomatic mission of the Democratic Republic of Korea (DPRK), according to Bosworth.
U.S. officials said there was no set timetable for the next round of talks and a senior State Department official suggested fresh discussions any time soon were unlikely.
"We do think it's going to be not a matter of days and weeks but probably a matter weeks and months before we're going to be able to really know where we're going next on this," the U.S. official, who spoke on condition of anonymity, told reporters. "We expect it to take some time for them to digest what we talked about in Geneva."
URANIUM ENRICHMENT KEY QUESTION
The talks on Tuesday were delayed at the request of North Korea, the U.S. diplomatic mission said earlier in a brief statement that declined to elaborate.
The morning session was canceled but the delegations had a joint lunch at the DPRK mission followed by an hour of talks.
Bosworth was accompanied by Glyn Davies, the outgoing U.S. ambassador to the U.N. nuclear watchdog agency who has been named his successor, in the Geneva talks.
North Korean leader Kim Jong-il told Chinese Vice Premier Li Keqiang that a moribund 2005 deal should be the basis for new talks about Pyongyang's nuclear activity, Chinese state media said on Tuesday, leaving unanswered a key question on uranium enrichment. The North's uranium enrichment program is not specifically referred to in the 2005 deal.
In his meeting with Li, Kim repeated that North Korea was willing to revive six-party talks it abandoned after the United Nations imposed sanctions for a long-range North Korean missile test. Pyongyang conducted a second test the following month.
"Kim said the DPRK hopes the six-party talks should be restarted as soon as possible," said the Xinhua news agency report of the Kim-Li meeting in North Korea on Monday night.
The North says it is enriching uranium only for power generation and argues that the 2005 agreement respects its right to peaceful uses of nuclear energy.
(Additional reporting by Chris Buckley and Ben Blanchard in Beijing, Jeremy Laurence in Seoul, and Arshad Mohammed in Washington; editing by Michael Roddy, Eric Beech and Todd Eastham)