The U.S. is anticipating that North Korea will return the remains of some 55 American service members on Friday, which is the 65th anniversary of the signing of the armistice that ended fighting in the Korean War, a U.S. official told Fox News.

The official noted that the return is not certain until the U.S. plane set to retrieve the remains departs from the northeastern city of Wonsan with the remains.

The return of the American remains lost in the Korean War was a major commitment by North Korean leader Kim Jung Un to President Trump at their summit in Singapore last month.

The remains -- if all goes well -- would be flown to the U.S. airbase of Osan in South Korea, where they would be catalogued and then flown to a Hawaii processing center next Wednesday.

Earlier this week, an American research group reported that North Korea had begun dismantling its main missile-engine test site, which could be another sign that a thaw is taking place between the two countries.

In June, Pentagon officials told Fox News that the U.S. was expected to accept as many as 200 sets of remains from North Korea within days.

Days later, the U.S. moved about 100 caskets to the DMZ in anticipation of the handover of the remains, but the transfer never took place.

North Korean officials were also no-shows earlier this month for a meeting with the U.S. regarding the remains of the Korean War dead, but U.S. Secretary of State Mike Pompeo downplayed the snub, telling reporters before leaving Pyongyang that the meeting "could move by one day or two."

Fox News' Lucas Tomlinson contributed to this story.