Assistant U.S. Secretary of State for East Asia Kurt Campbell says North Korea should show commitment to advancing inter-Korean relations in the future.

Campbell said Wednesday, following North Korea’s move to promote Kim Jong-il’s son Jong-un to powerful political and military posts, that the U.S. hopes to see a signal that new Pyongyang leaders or institutions in North Korea accept the commitments the North made in 2005 to denuclearize.

He said that Washington’s priority is on seeing North Korea display the will to pursue future-oriented ties with the South and to resume cross-border dialogue.

Campbell also put an emphasis on easing the tensions that followed the sinking of South Korea’s “Cheonan” naval vessel in March in waters near the inter-Korean maritime border in the Yellow Sea.