Washington CNN  — 

North Korean officials did not show up to a planned meeting with US officials at the demilitarized zone Thursday, where they were expected to continue discussions on repatriating the remains of Americans killed during the Korean War, a senior US official tells CNN.

State Department spokeswoman Heather Nauert said Thursday that the North Koreans postponed the meeting the day it was supposed to take place.

Citing a senior North Korean official, Nauert said, “Vice Chairman Kim Yong Chol ‎agreed in his dialogue with Secretary (of State Mike) Pompeo to have his team meet with an American team on or about July the 12th to move forward with the repatriation of American service members’ remains. Mid-day, on July the 12th, they contacted us and offered to meet on Sunday July the 15th,” Nauert said in a statement. “We’ll be ready.”

Pompeo ignored a question about the apparent snub when asked by reporters traveling with him in Brussels, Belgium, on Thursday.

The development is likely to fuel growing skepticism over North Korea’s commitment to a complete denuclearization of the Korean Peninsula as promised during last month’s meeting between President Donald Trump and Kim Jong Un in Singapore.

Trump has touted the return of remains as one of the successes of his historic June 12 summit with Kim.

CNN reported last month that the Trump administration is expecting North Korea to return up to 200 sets of remains and that planning for the exchange has been underway. About 100 wooden transport cases were sent to the DMZ in recent weeks to prepare for receiving US troop remains.

But Thursday’s no-show comes after Kim scuttled a rendezvous with Pompeo during his trip to Pyongyang.

Pompeo last week failed to demonstrate any progress on denuclearization talks, leading one source with knowledge of the discussions to say the White House felt it went “as badly as it could have gone.”

“The North Koreans were just messing around, not serious about moving forward,” the source told CNN’s Michelle Kosinski, adding that Pompeo had been promised a meeting with Kim, and the fact that it failed to materialize sent a big message.

The Defense Department estimates there are up to 5,300 sets of US service member remains still somewhere in North Korea. A total of 7,697 personnel remain unaccounted for from the Korean War. Some are pilots who were shot down, some are ground troops, others may be those who died in prisoner-of-war camps.

While in Brussels for the annual NATO summit on Thursday, both Trump and Pompeo expressed confidence in the diplomatic process with North Korea despite lacking of tangible signs of progress.

Pompeo said his counterpart Kim Yong Chol in North Korea “made a commitment” that North Korea intends “to denuclearize.”

Trump also again touted his meeting with the Kim Jong Un, calling it “an amazing meeting” and saying the two “established very good relations.”

CNN’s Barbara Starr contributed to this report.