President Trump and North Korean leader Kim Jong Un delivered a joint statement Tuesday seeking a landmark deal to denuclearize the Korean Peninsula. But nestled in the document was a short bullet point that addresses a long-running concern of U.S. veterans groups: the recovery of the remains of thousands of American troops who were killed or captured in North Korea during the Korean War.

On Tuesday, the two countries agreed to “commit” to recovering the remains of fallen troops, “including the immediate repatriation of those already identified,” according to the document.

The statement represents a significant victory for veterans groups that lobbied forcefully behind the scenes for a renewed effort to recover remains in an environment where many non-nuclear issues, including human rights and the return of Japanese abductees, were left unaddressed in the joint statement.

The remains of 5,300 American forces who were killed or captured in North Korea during the war remain unaccounted for north of the demilitarized zone, resting in cemeteries, former labor camps and battle sites. From 1990 to 2005, joint U.S.-North Korean search teams repatriated 229 sets of remains. But the cooperation between the United States and North Korea was abruptly suspended in 2005 as political relations deteriorated.

In recent days, Secretary of State Mike Pompeo told his negotiating team, led by U.S. Ambassador to the Philippines Sung Kim, that the POW issue is important to Trump, and he “instructed Kim to negotiate for it,” State Department spokeswoman Heather Nauert said. Trump, during a news conference Tuesday, said that he had received “countless” phone calls from Americans asking for help on the issue.

“So many people, during the campaign, would say, 'Is there any way you can work with North Korea to get the remains of my son back or father back?' ” Trump said. “I said we don’t get along too well with that particular group of people. Now we do. And he agreed to that so quickly and nicely. It was a nice thing.”

As Trump headed into his landmark meeting with Kim Jong Un earlier in the day, a top Defense Department official told families of the missing troops that securing the remains and resuming recovery efforts is a top priority for negotiations.

“We are in close communication with the White House, with the Department of Defense and with the Department of State that this mission needs to be part of the dialogue” at the summit in Singapore, Kelly McKeague, director of the Defense POW/MIA Accounting Agency, told 258 family members who gathered in mid-May in Louisville for a summit of their own.

“It's a humanitarian mission and one that the North Koreans need to live up to their obligations on, as most nations do,” said McKeague, a retired Air Force major general, according to a recording of his speech. He explained that North Korea and, as of last fall, Cambodia are the only outliers in cooperative recovery efforts with 46 countries. “We continue to enjoy an understanding, at least within the U.S. government, of communicating that to the North Koreans.” He said the North Koreans are holding the remains of 200 additional American troops.

On Monday, the Veterans of Foreign Wars, which has for years promoted recovery efforts for fallen troops, sent a letter to Trump, Pompeo and Defense Secretary Jim Mattis urging that a repatriation agreement be on the table during the president's negotiations with Kim.

“As the leader of the free world, we urge you to do everything in your power to ensure that those who paid the ultimate price for freedom during the Korean War are finally returned home to their families,” Keith Harman, VFW's commander in chief, wrote. He called the return of missing troops' remains an unsettled issue of “paramount importance” to the VFW and its 1.7 million members.

More than 35,000 American forces died on the Korean Peninsula between 1950 and 1953. The U.S. government estimates that 7,702 are still unaccounted for, with about 2,400 in South Korea.

“We owe a profound debt of gratitude to all U.S. service members, especially to those who gave their lives to uphold America’s freedom and values,” said a State Department official who was not authorized to speak publicly about the meeting. “Around the world, U.S. embassies and missions work closely with the U.S. Department of Defense to recover those who made the ultimate sacrifice, and to bring them home.”

A person familiar with the discussions said the agreement was a surprise, given the almost exclusive focus of negotiators on the nuclear issue.

In a normal negotiation, a noncontroversial, humanitarian issue such as finding the remains of fallen troops probably would be used as a confidence-building measure in advance of a leadership-level meeting. But Trump flipped the script on its head, opening the talks with a meeting with Kim and raising the most difficult issues, such as denuclearization, at the outset.

Last week, South Korean President Moon Jae-in expressed hope that Pyongyang might allow teams to start recovering the remains of troops from the demilitarized zone, the 154-mile-long divide between the two countries. More than 120,000 South Korean soldiers who fought in the war remain unaccounted for, many thought to be lost on the North Korean side.

“We will continue efforts to recover the remains of members of the military and police who fell during the Korean War until we find the last remaining person,” Moon said in a speech on June 6.

The Defense POW/MIA Accounting Agency, formed in 2015 to bring together disparate recovery efforts across the government, estimates that 82,000 service members from the World War II era through the Persian Gulf  and Iraq wars are unaccounted for. The great majority, almost 73,000, fought in World War II.

American teams had conducted almost three dozen recovery operations in North Korea before President George W. Bush stopped the missions, claiming Americans' safety was not assured.

North Korea's Kim Jong Un and President Trump met for the first time on June 12. Here are key moments from the summit in Singapore. (The Washington Post)

“It's no big secret that we’re still trying to resolve those cases from Korea,” POW/MIA Accounting Agency spokesman Charles Prichard said in an interview. In the intervening years, defense officials have continued to do archival research, he said, and to identify remains, including 19 from the Korean conflict this fiscal year.

The agency holds regular meetings with families to update them on technology and progress in their cases. The gathering at the Crowne Plaza Hotel in Louisville on May 19 drew people from Alabama, Illinois, Kentucky, Ohio, Tennessee and West Virginia.

McKeague told the families that his agency's mission has received growing interest and support from Congress, which boosted its $146 million budget by $50 million this year. Even Russia agreed this year to allow recovery experts to begin a mission to find the remains of World War II troops in the vast country, the first effort in 15 years, he said.