Senior US and North Korean envoys held rare face-to-face talks Saturday in New York, boosting hopes of progress in stalled nuclear talks and paving the way toward increased bilateral engagement.

Ri Gun, a deputy negotiator in stalled six-nation talks over the hermit state's nuclear program, arrived on Friday with his delegation on the eve of the meeting with the US special envoy on North Korea's nuclear disarmament.

"Ambassador Sung Kim took the opportunity to meet with him (Ri) in New York on October 24 to convey our position on denuclearization and the six-party talks," State Department spokesman Noel Clay said in a statement.

Kim and US Principal Deputy Assistant Secretary of Defense for Asian and Pacific Security Affairs Derek Mitchell will participate in the Northeast Asia Cooperative Dialogue in San Diego beginning Sunday that Ri is also expected to attend, Clay added.

North Korea has long sought to meet exclusively with the United States and gain recognition as a nuclear weapons state.

Ri's rare visit fueled fresh speculation that North Korea is preparing to return to talks about its nuclear weapons program with China, Japan, Russia, South Korea and the United States.

US Assistant Secretary of State for East Asian and Pacific Affairs Kurt Campbell said this week that Washington was ready to meet one-on-one with Pyongyang but only if it "rapidly" leads to full-fledged denuclearization talks in the six-nation forum.

The United States "would be prepared for, in the right circumstances at some point, some initial interaction" with the impoverished and reclusive state so long as the move "would lead rapidly to a six-party framework," he said.

On October 6, North Korean leader Kim Jong-Il told Chinese envoys the North was willing to return to six-way talks, but insisted it first negotiate directly with the United States to repair "hostile relations."

The San Diego meeting is organized by the University of California's Institute on Global Conflict and Cooperation, which released a study urging Washington to scrap its policy of isolating Pyongyang and embrace economic engagement to curb the reclusive communist state's provocative behavior.

It namely recommended dropping objections to Pyongyang's entry into global financial institutions like the International Monetary Fund.

The study released Thursday flew in the face of the approach undertaken by President Barack Obama, who has pushed to toughen sanctions after Pyongyang's string of incitements, including a nuclear test and missile launches.

Ri's trip followed Washington's unusual decision to grant a visa to the North Korean officials, but Clay stressed that Ri "traveled to the US on the invitation of US private organizations."

Prior to the San Diego event, the North Korean delegation was scheduled to attend a seminar in New York hosted by the National Committee on American Foreign Policy and the Korea Society.

The possible diplomatic overtures come after senior US officials fired tough words at Pyongyang.

Secretary of State Hillary Clinton has warned that the United States will never have "normal, sanctions-free relations" with a nuclear-armed North Korea and demanded Pyongyang's full nuclear disarmament.

During a visit to South Korea on Thursday, US Defense Secretary Robert Gates labeled North Korea a grave threat to international peace and promised to keep Washington's allies in East Asia under its nuclear umbrella.

The United States has 28,500 troops in South Korea, bolstering that nation's 655,000-strong armed forces against the North's 1.2 million troops.

Speculation is also rife about a possible summit between the two Koreas, after Chinese Premier Wen Jiabao said earlier this month that the North Korean leader has expressed a desire to improve ties with the South.

The Koreas held summit talks in 2000 and 2007 and agreed on a series of reconciliation events and joint economic projects.