Draped in white-and-blue United Nations flags, boxes of remains from the Korean War were unloaded from a group of vans one by one under the scorching sun at US Osan airbase in South Korea on Wednesday.

A total of 55 boxes were then carried by the honor guard from the UN Command and loaded onto two C-17 Globalmaster cargo planes heading for Hawaii. Dozens of service members and a military honor guard lined up on the tarmac to mark the return of the fallen troops.

After four F-16 fighter jets flew over the tarmac, with one of them flying vertically, to honor those sacrificed their life during the Korean War, one cargo planes flew out of Osan Air base at around 8 p.m. The other one took off around two hours later for "maintenance concern," according to the UNC.

“This is solemn reminder that our work is not complete until all have been accounted for no matter how long it takes to do so,” UNC Commander Gen. Vincent Brook said during a speech before he went to the tarmac to send off the remains.

The occasion was a part of the solemn ceremony to mark the return of what is believed to be the remains of US soldiers from the Korean War. Last week, the remains were flown out of North Korea and arrived at Osan Air Base.

During the Singapore summit in June, US President Donald Trump and North Korean leader Kim Jong-un agreed on the immediate repatriation of the remains of prisoners of war, those missing in action and those already identified.

About 7,700 US soldiers are listed as missing from the Korean War, and 5,300 of the remains are believed to still be in North Korea. The war killed millions of the people and soldiers, including 36,000 American soldiers.

"Encouraged by recent cooperation with North Korea on this humanitarian effort ... we have gathered as the successors of the UNC and the Republic of Korea, and as the beneficiaries of the noble sacrifices of those who for a short while longer will remain nameless yet in our presence,” Brooks said during the ceremony.

Including Brooks, some 500 soldiers and officials from the US, South Korea and UNC member states attend the ceremony. Among them are South Korea’s Defense Minister Song Young-moo and US Ambassador Harry Harris.

The remains were flown to Hawaii after the repatriation ceremony for in-depth forensic analysis, in some cases using mitochondrial DNA profiles, at a Defense Department laboratory to attempt to establish individual identifications.

A senior official from Defense POW/MIA Accounting Agency said the agency has determined those remains are human and most likely American. The official also confirmed a single military dog tag was provided with the remains and that the family of that individual has been notified.

“Keep in mind that it’s not necessarily the case that” the person identified in the dog tag will be among the remains, said Dr. John Byrd, director of scientific analysis for DPAA, said during a press briefing before Brook’s speech.

A US defense official told the Associated Press that when North Korea handed over 55 boxes of bones that it said were US war remains, it provided a single military dog tag but no other information that could help US forensics experts determine their individual identities.

By Yeo Jun-suk (jasonyeo@heraldcorp.com)