North Korea on Friday handed over the remains of some U.S. soldiers who died during the 1950-53 Korean War, giving new momentum to a diplomatic detente that had shown signs of stalling in recent weeks.

Exactly 65 years after the signing of an armistice that ended hostilities in the conflict, a U.S. military plane flew the remains to Osan Air Base in South Korea after collecting them from North Korean officials in the port city of Wonsan.

“We are encouraged by North Korea’s actions and the momentum for positive change,” the White House said in a statement. “Today’s actions represent a significant first step to recommence the repatriation of remains from North Korea and to resume field operations in North Korea to search for the estimated 5,300 Americans who have not yet returned home.”

A formal repatriation ceremony would be held at Osan Air Base on Wednesday, the statement said.

President Trump welcomed the news in a tweet. “After so many years, this will be a great moment for so many families. Thank you to Kim Jong Un,” he said.