President Barack Obama's special envoy held last-minute discussions on his upcoming trip to North Korea, huddling Monday with South Korean officials over how best to bring Pyongyang back to international nuclear talks, a Seoul official said.

Stephen Bosworth's three-day visit to Pyongyang starting Tuesday will include the first formal bilateral talks between the U.S. and the North since Obama took office in January. The two countries last met one-on-one on the sidelines of now-stalled six-nation nuclear talks in Beijing in December 2008.

On Monday, Bosworth met with South Korea's chief nuclear envoy, Wi Sung-lac, to discuss the trip. He told Wi that the U.S. intentionally decided to start the North Korea trip from South Korea _ a remark seen as meaning that the two allies are working closely together.

"It's not an accident. We intended that," Bosworth told Wi at the start of their meeting.

South Korean Foreign Ministry spokesman Moon Tae-young said various issues were discussed at the meeting, aimed at achieving the goal of Bosworth's trip: bringing North Korea back to the nuclear negotiating table, and getting the regime to recommit to denuclearization.

"For now, it is difficult to predict the outcome of his trip," Moon said. "We hope there will be good results, including North Korea's return" to the six-nation nuclear talks involving China, Japan, the two Koreas, the U.S. and Russia.

Moon said Bosworth also met with Foreign Minister Yu Myung-hwan and presidential security adviser Kim Sung-hwan.

Bosworth is scheduled to fly to the North from a U.S. air base near Seoul. While in Pyongyang, he is expected to meet with First Vice Foreign Minister Kang Sok Ju _ the country's top nuclear strategist and leader Kim Jong Il's chief foreign policy brain _ according to South Korea's Yonhap news agency.

North Korea has pushed for direct talks with the U.S. since it pulled out of the nuclear negotiations in protest of international criticism of a rocket launch in April. The North claims it was compelled to develop atomic bombs to cope with what it calls "U.S. nuclear threats."

The U.S., which denies making any threats, has said it is willing to engage the North in direct discussions but has stressed they must lead to an end of Pyongyang's boycott of the six-party talks.

Professor Kim Yong-hyun of Seoul's Dongguk University cautioned against high expectations.

"Realistically speaking, it's difficult to make breakthroughs in all issues in just one meeting," he said.