The 55 sets of human remains handed over by North Korea to the United States may include troops from other nations that fought in the Korean War after it was confirmed that only one identification tag was included with the bodies. A US defence official told the Associated Press that it will probably take months, if not years, to identify with any certainty the identities of the troops. As the remains were due to land on US soil for the first time on Wednesday, John Byrd, director of scientific analysis at the Defense POW/MIA Accounting Agency (DPAA), the US agency that deals with soldiers missing in action, said preliminary findings suggested that "they are likely to be American remains" as they were consistent with those repatriated in the past. "But I would caution… to keep in mind that it's not necessarily the case that the dog tag goes with the remains… in the box," he added, underscoring the challenges of identifying the recovered remains. There are no further details about the military dog tag that was handed over when a US military transport aircraft flew to Kalma Airport, on the outskirts of the North Korean city of Wonsan, on Friday. The aircraft returned to the US Air Force base at Osan where the remains were handed over to representatives of the DPAA. The United Nations Command held a ceremony at the air base on Wednesday to mark the formal repatriation. The event was attended by Song Young-moo, the South Korean defence minister, and General Vincent Brooks, the commander of the UNC. Repatriation | Identifying the dead of the Korean war Following the ceremony, the caskets containing the remains are being flown to the agency’s laboratories at the Pearl Harbor-Hickam military base in Hawaii for full forensic examinations to begin on US soil. The remains within each box may not be those of a single person and are likely fragments of bones, said Paul Cole, an expert on recovery of soldiers missing in action and prisoners of war, who worked as a visiting scientific fellow at Hawaii's Central Identification Laboratory. "Problems such as inability to get DNA from bones and lack of a DNA reference sample from the family can be major stumbling blocks," added Chuck Prichard, director of public affairs for the Defense POW/MIA Personnel Accounting Agency, the US military's main unit for finding and identifying missing members. Jim Mattis, the US defence secretary, stated last week that the return of the remains is a positive step, but added that there are no guarantees they are of US military personnel. “We don’t know who is in those boxes”, he said, adding that some might be from other nations that committed troops to the 1950-’53 Korean War. “They could go to Australia”, he said. “They have missing. France has missing. Americans have. There’s a whole lot of us. So this is an international effort to bring closure for those families”. While US officials are clearly disappointed that the North Koreans did not provide more information on the bodies that were being repatriated, it has raised the possibility that at least some of them may be of British personnel killed in the conflict. Some 1,108 British troops were killed in the war, with 336 still listed as missing.