The Defense Department agency that accounts for missing American service members from past wars hopes to negotiate the resumption of joint operations to recover remains in North Korea, an official said Thursday, calling such efforts a “sacred obligation.”

Defense POW/MIA Accounting Agency Director Kelly McKeague, speaking at the Pentagon, said North Korean leader Kim Jong Un committed to recovering remains when he met with President Trump in Singapore in June.

Talks on resuming field operations, which ran for a decade before they were suspended by the Bush administration in 2005, could take place soon, McKeague said. While North Korea at times has unilaterally handed over boxes of remains, as the country did this week, more fruitful in the eyes of U.S. officials have been joint efforts to find and recover remains with American personnel on the ground.

“Given the fact that the North Koreans reaffirmed that commitment to Secretary Pompeo last month, we fully expect that there might be an environment in which case they would be open to sitting down to negotiate,” he said.

The United States is preparing to analyze and identify remains of presumed U.S. war dead that North Korea handed over in 55 boxes last week, the largest number of boxes of remains Pyongyang has returned at any one time since the modern process began in the 1990s.

The U.S. military sent 200 boxes to the demilitarized zone between North and South Korea in anticipation of the latest transfer, but North Korea handed over only 55 boxes, McKeague said, explaining that U.S. officials didn’t know the specifics in advance. The last time North Korea handed over remains, in 2007, the country transferred six boxes, out of which seven individuals were identified, he said. 

The Hawaii military laboratory that analyzes and identifies the remains is planning to double the number of people working on its Korean War team to 10 from five as a result of this week’s influx, chief scientist John Byrd said, noting that the process of DNA sampling would begin immediately.

Byrd cautioned that the 55 boxes did not necessarily equate to the remains of 55 individuals. He said many of the remains appear to have come from a village associated with the Battle of Chosin Reservoir, a harrowing fight against Chinese forces in late 1950 that claimed thousands of American lives. 

About 7,700 American service members are missing from the battlefields of the Korean War, including some 5,300 believed to have died north of the 38th parallel in what is now North Korea.

Family members of about 92 percent of those missing have given DNA samples, according to McKeague. He described the extensive efforts by the United States to identify those service members who remain missing as a “sacred obligation and moral imperative.” 

The United States has sent North Korea $22 million since 1990 as it recovered an estimated 629 sets of remains, according to a spokesman for the U.S. military. Much of that money was sent as reimbursement for the costs incurred during the recovery process, which for years involved North Korean officials accompanying American delegations as they traveled to war sites and obtained remains. 

McKeague said North Korea did not receive any payment for the transfer this week. 

“There are no costs associated with this particular repatriation,” he said. “None whatsoever. No caveats. No conditions.” 

McKeague did not say whether the United States would continue reimbursing North Korea, should field operations in the country resume.

“Looking back on it, I would say it was challenging but very successful,” said Byrd, who took part in the joint field operations that stretched from the mid-1990s to the mid-2000s. He said he “would go back in an instant if we were asked to.” 

The agency’s officials expressed confidence that the remains the North Koreans handed over this week were indeed those of Americans service members who died during the war.

According to Byrd, the boxes contained items typical of what the agency normally recovers from battlefields — boots, canteens, buttons, buckles and pieces of uniforms. U.S. officials say they have already contacted the family of a service member whose dog tag was returned.

Despite such clues, the process of identifying the remains is onerous. 

The lab will begin by taking DNA samples from the remains and checking to see whether they match those of other remains in the inventory or those that family members of missing service members have provided. The lab’s Korean War team will then pursue any matches. 

Lab officials also will check to see whether any teeth are among the remains, and if so, compare them with a database of dental records of service members missing from the Korean War.