In this file photo taken on Aug. 1, 2018, flag draped transfer cases with the remains of U.S. soldiers repatriated from the Democratic People's Republic of Korea are seen during a repatriation ceremony after arriving at Joint Base Pearl Harbor-Hickam, Honolulu, Hawaii. (Xinhua/AFP)

WASHINGTON, Sept. 11 (Xinhua) -- U.S. Defense Secretary James Mattis revealed on Tuesday that the United States has identified two sets of Korean War remains among those that had been returned by Pyongyang over a month ago.

Mattis told reporters at the Pentagon that experts chose to focus on these two sets of remains as they thought "they had a better chance," considering reasons including where the remains had been found and the background Washington had.

"So there's been, already, some closure for a couple of families that have waited many, many years for this," added the Pentagon chief.

Mattis did not publicly identify the remains. He also said that consultations are going on about the repatriation of more Korean War remains.

Fifty-five boxes of human remains from the 1950-53 Korean War were handed over by the Democratic People's Republic of Korea (DPRK) in late July, seen as a sign of progress after the historic Singapore meeting between U.S. President Donald Trump and the DPRK's top leader Kim Jong Un.