A U.S. State Department specialist on Korean affairs is planning to travel to North Korea to discuss an impasse in six-nation nuclear disarmament negotiations.

State Department spokesman Sean McCormack says Sung Kim will leave Tuesday. He is scheduled to have meetings in Pyongyang on Thursday.

Kim visited North Korea in late April and met with the head of North Korea’s delegation to the disarmament talks.

Those discussions have been stalled since last year over what North Korea will include in a declaration of its nuclear programs.

The U.S. says the North missed a year-end deadline to complete the declaration it had agreed to provide to the other countries in the negotiations.