Fifty-five cases of possible American remains were flown out of North Korea by a U.S. Air Force C-17 cargo aircraft today, setting up their arrival next week at Joint Base Pearl Harbor- Hickam for identification as part of a historic turnover brokered between President Donald Trump and North Korean leader Kim Jong Un.

“A U.S. Air Force C-17 aircraft containing remains of fallen service members has departed Wonsan, North Korea,” the White House said in a statement. “It is accompanied by service members from United Nations Command Korea and technical experts from the Defense POW/MIA Accounting Agency.”

DPAA, which searches for, recovers and identifies missing American war dead, has a state-of-the-art identification lab at Hickam where the bones likely will be laid out on examination tables for analysis.

The C-17 was transferring the remains to Osan Air Base in South Korea, where a formal repatriation ceremony will be held Wednesday, the White House said.

At the June 12 Trump-Kim summit in Singapore, the two leaders took “a bold first step” to achieve denuclearization on the Korean Peninsula and transform relations, the statement said.

“Today, the chairman is fulfilling part of the commitment he made to the president to return our fallen American service members,” the White House said. “We are encouraged by North Korea’s actions and the momentum for positive change.”

Speaking at a Pacific Air Forces command change Thursday morning, Adm. Phil Davidson, head of the Oahu-based U.S. Indo-Pacific Command, said, “North Korea remains our most immediate challenge.”

But he added that “it will be Pacific Air Forces on the ground in North Korea that will repatriate some of our Korean war dead later today.”

U.S. Forces Korea said that “immediately following” Wednesday’s repatriation ceremony in South Korea, “the remains will be flown to Hawaii for further processing under the Defense POW/MIA Accounting Agency.”

Defense Secretary James Mattis said previously that the remains, once turned over, would be checked at Osan to “make sure that they appear to be what we think they are.”

They will be part of an “honorable carry” ceremony at Hickam with flag-draped caskets escorted by military members to the accounting lab.

Forensic experts will closely examine the bones to determine whether they are fallen Americans from the 1950-53 Korean War, and verify which bones are part of an individual set.

Between 1990 and 1994 the United States received 208 boxes of remains from North Korea known as K-208. North Koreans probably excavated a lot of the remains from cemeteries, battlefields or foxhole graves, the lab had said. But then the North tried to create skeletons using mismatched parts.

Forensic anthropologists with the Hawaii lab had to go bone by bone making physiological and DNA comparisons. Out of a potential 400 individuals, 181 had been identified by late June.

From 1996 to 2005, meanwhile, the United States conducted 33 “joint field activities” in North Korea using Hawaii-based personnel, with 153 identifications made out of 229 sets of recovered remains.

In two cases near the Chosin Reservoir, nearly complete skeletons were found by U.S. personnel along with bits of uniform, buttons and a belt buckle, .38-caliber bullets and a tent pole.

Remains recovered by the United States have been relatively intact because the soldiers and Marines who died were mostly foot soldiers, as compared with pilots in Southeast Asia whose bodies suffered severe trauma in airplane and helicopter crashes.

Some 36,000 Americans were killed in the Korean War. The accounting agency said 7,700 service members are unaccounted for, with about 5,300 in North Korea.

Returning U.S. war remains was a rare tangible commitment Kim made during his meeting with Trump in Singapore, where a vague aspirational goal for a nuclear-free Korean Peninsula was set without describing when and how that would occur.

North Korea today marked the 65th anniversary of the end of the Korean War as the day of “victory in the fatherland liberation war.”

Trump, meanwhile, proclaimed July 27 as National Korean War Veterans Armistice Day, noting the cease-fire agreement that ended the fighting.

“For three brutal years our armed forces and allies fought valiantly to stop the spread of communism and defend freedom on the Korean Peninsula,” Trump said. “On National Korean War Veterans Armistice Day, we remember the bravery and sacrifices of those who fought and died for this noble cause.”

The remains’ return could be followed by strengthened North Korean demands for fast-tracked discussions with the United States on reaching a declaration to formally end the war with a peace treaty.

The Associated Press contributed to this report.