"Unfortunately, we have not yet received a complete and correct declaration and we urge North Korea to deliver one soon, so that we can all get the benefits offered in the six-party process," U.S. National Security Council spokesman Gordon Johndroe told reporters.

In addition, the State Department also disputed the DPRK's statement that it had handed over a list of its nuclear programs ahead of a year-end disarmament deadline.

"The North Koreans need to get about the business of completing this declaration," State Department Spokesman Sean McCormack said, noting "It is another data point that will indicate that they are in fact serious about denuclearizing the Korean peninsula."

The DPRK's Foreign Ministry issued a statement on Friday, saying that it had declared its nuclear programs to the United States in November.

"Now that other participating nations delay the fulfillment of their commitments, the DPRK is compelled to adjust the tempo of the disablement of some nuclear facilities on the principle of 'action for action'," the statement said.