The remains of 22 servicemen killed on a Japanese-controlled island during World War II returned home to U.S. soil on Thursday, the Defense POW/MIA Accounting Agency said.

“Today, we welcome home more than 20 American servicemen still unaccounted for from the battle of Tarawa during World War II,” said acting Secretary of Defense Richard V. Spencer in a statement acknowledging the repatriation on behalf of a grateful nation.

“We do not forget those who gave the ultimate sacrifice and it is our duty and obligation to return our missing home to their families and the nation. Thank you to everyone who took part in this repatriation.”

The Defense POW/MIA Accounting Agency transferred the remains from Tarawa in 22 cases to Joint Base Pearl Harbor-Hickam, Hawaii, though remains from additional servicemembers could possibly be commingled with them, Stars and Stripes reports.

According to the agency, the servicemen were killed during the Battle of Tarawa, which was part of the larger Operation GALVANIC that commenced Nov. 20, 1943, to capture Japanese-held territory within the Gilbert Islands.

During the operation, approximately 1,000 Marines and Sailors were killed and 2,000 more were wounded over several days of fighting that “virtually annihilated” the Japanese on the Pacific Ocean island, the State Department said.

Tarawa is now part of the nation of Kiribati and efforts to repatriate remains of U.S. servicemen from the island have been ongoing since 1946, the agency said.

In March, searchers with the nonprofit organization History Flight discovered a mass grave with remains believed to be from members of the 6th Marine Regiment. The transfer Thursday represents a portion of remains found at that time, according to the Stars and Stripes report.

History Flight has been searching for World War II remains in Tarawa since 2007. In 2015, the group uncovered the bodies of 35 U.S. troops, including Medal of Honor recipient 1st Lt. Alexander Bonnyman Jr., who died leading a doomed assault on a Japanese bunker.

Of the 16 million Americans who served in World War II, more than 400,000 died during the war. Currently there are 72,692 service members still unaccounted for from the conflict, of which approximately 30,000 are assessed as possibly-recoverable.

UPI contributed to this story