SEOUL, South Korea (AP) — A senior North Korean envoy's meeting with U.S. Secretary of State Mike Pompeo has been delayed, throwing already deadlocked diplomacy over the North's nuclear weapons into further uncertainty.

The State Department said in a short statement Wednesday the officials would meet later "when our respective schedules permit." It offered no reason, and the North's propaganda services has not mentioned the meeting.

After last year's fears of war, North Korea and the United States are trying to revive stalled diplomacy meant to rid the North of its nuclear weapons. There was much talk of the possibility of success following a meeting in June between President Donald Trump and North Korean leader Kim Jong Un, but in the months since there has been little to quiet skeptics who believe the North will never give up weapons it has described as necessary to counter a hostile Washington.

Pompeo was supposed to travel to New York on Thursday to meet with his North Korean counterpart, Kim Yong Chol.

South Korea's presidential office said the government will later announce its stance over the postponed meeting.

The U.S. State Department earlier said that the top U.S. envoy for North Korea, Stephen Biegun, was to join Pompeo and Kim to discuss how to get to what it calls "achieving the final, fully verified denuclearization" of North Korea.

Last Friday, North Korea's Foreign Ministry criticized the U.S. for its continued support of sanctions and hinted it may resume nuclear development. 

The North Korean statement warned North Korea could bring back Kim Jong Un's trademark "byongjin" policy of simultaneously advancing its nuclear force and its economic development if the United States doesn't change its stance. The North stopped short of threatening to abandon ongoing nuclear negotiations with Washington.