A high-ranking North Korean official has been denied entry to the United States, apparently in response to the North's steadfast refusal to resume a fourth round of multilateral negotiations about its nuclear program..

Sources say Lee Geun, Deputy Director-General of the American Affairs Bureau at North Korea's Foreign Ministry, had applied for a U.S. visa to attend a forum on the North Korean nuclear issue that was held in New York on Tuesday, but the application was rejected.

Lee was previously allowed to attend a similar seminar in August. Observers speculate Washington may refrain from contacts with North Korean officials as long as the six-party talks remain in limbo.

With the visa denial, an anticipated meeting between Lee and Joseph R. DeTrani, a U.S. State Department envoy to North Korea, was thus cancelled. North Korea's Ambassador to the U.N. Han Song-ryol had attended the forum in Lee's place.