Seoul , South Korea -LRB- CNN -RRB- -- The Obama administration 's first high-level direct talks with North Korea yielded no promise by Pyongyang to return to six-party negotiations aimed at ending its nuclear program , but Secretary of State Hillary Clinton on Thursday nonetheless called the meeting `` quite positive . '' In Washington , Clinton said she agreed with special envoy Stephen Bosworth that the talks were `` very useful , '' adding , `` It does remain to be seen whether and when the North Koreans will return to the six-party talks , but the bottom line is that these were exploratory talks , not negotiations . '' North Korea has refused to return to the talks conducted by the United States , Russia , China , South Korea and Japan , insisting that it wants to talk directly with the U.S. . In April , Pyongyang declared the talks `` dead '' in anger over international criticism of its nuclear and missile tests this year . Clinton previously said the United States was willing to meet bilaterally with North Korea but only within the framework of the six-party talks . She also has warned the United States will not normalize ties with Pyongyang or lift sanctions unless North Korea takes irreversible steps toward dismantling its nuclear program . Of his three-day visit , Bosworth said , `` My purpose ... was to facilitate the resumption of the six-party talks and to reaffirm the goal of fully implementing the September 2005 joint statement . '' Holding a news conference Thursday in Seoul after his visit to North Korea , Bosworth said , `` I communicated President Obama 's view that complete denuclearization of the Korean Peninsula is a fundamental undertaking of the six-party process ... and that the absence of progress on denuclearization is an obstacle to improving our relations . '' As Obama `` has made it clear , the United States is prepared to work with allies , partners in the region to offer ... North Korea a different future , '' he said . Bosworth said he held talks with North Korean officials , but not President Kim Jong Il , because `` we did not ask '' for a meeting with the leader . He said they did not make plans for a future meeting . Many observers are wondering what 's behind the North 's latest moves , and some said Bosworth 's trip is a positive . `` The visit gives North Korea a lot of ` face , ' a sense of importance , '' said Wenran Jiang , political science professor at the University of Alberta in Canada . Some analysts said North Korea might be trying to buy time . Earlier reports in Seoul claimed that North Korea is in the final stages of restoring its Yongbyon nuclear plant , which Pyongyang had begun to disable before walking away from the six-party talks . Given the secrecy of the North , those reports could not be verified . Analysts said North Korea also is desperate to break out of its diplomatic isolation and ease its economic pain , especially after the U.N. Security Council imposed tougher sanctions on the country in response to Pyongyang 's nuclear and missile tests . A joint statement issued by the six-party nations in September 2005 said North Korea had `` committed to abandoning all nuclear weapons and existing nuclear programs . '' CNN 's Jill Dougherty contributed to this report .