North Korea's top nuclear negotiator plans to discuss the resumption of six-party talks on his country's nuclear program during his visit to the U.S. in March, South Korea's Yonhap said on Friday.

The six-party talks came to a halt last April when North Korea walked out of negotiations in protest against the United Nations' condemnation of its missile tests. The North recently hinted that it was willing to return to the talks, but insisted it first negotiate directly with the United States to repair "hostile relations."

"I believe the dates for Kim [Kye-gwan]'s trip to the United States have already been set," a diplomatic source told Yonhap on the condition of anonymity.

The agency gave no exact dates of the visit by Kim, North Korea's deputy foreign minister who represents the country at the six-party talks.

Kim is currently discussing the resumption of the six-party talks in China, which, along with Russia, Japan, South Korea and the United States, is trying to persuade Pyongyang to abandon its nuclear program.

U.S. special envoy to North Korea Stephen Bosworth said after his visit to the country in December that both sides "deepened mutual understanding and narrowed differences," but Pyongyang had not clearly expressed its commitment to the return to nuclear negotiations in a multilateral format.

North Korea is banned from conducting nuclear or ballistic tests under UN Resolution 1718, adopted after North Korea's first nuclear test on October 9, 2006.

However, Pyongyang carried out a second nuclear test on May 25 last year, followed by a series of short-range missile launches, and has threatened to build up its nuclear arsenal to counter what it calls hostile U.S. policies.

The move led to the UN imposing new sanctions on North Korea banning the import and export of nuclear material and all weapons except small arms.