A U.S. State Department official says North Korea has yet to fully disclose its nuclear activities.

Korea Desk Director Sung Kim told reporters in Beijing that he did not receive a list of nuclear declarations from the North during his three-day visit there. He returned from a visit to Pyongyang that began Thursday.

He said he discussed with North Korean diplomats the disclosure of nuclear activities during his visit.

Kim said he reiterated that nuclear disclosure should be carried out in a perfect and precise way, hinting that he urged the North to fully declare its nuclear activities.

Kim is the first State Department official to visit North Korea since the top U.S. envoy to the six-way nuclear talks, Christopher Hill, made a visit in early December last year.