Vietnam has returned 23 sets of human remains believed to be those of Americans reported missing in action during the Vietnam War, a U.S. military spokesman said.

"Altogether 23 sets of remains were returned to us today (Thursday) in a ceremony at the (Hanoi) airport," said Maj. Dan Trout, spokesman for the U.S. Pacific Command.Trout said 21 sets of remains were discovered during unilateral searches by Vietnamese officials, and the other two were found during a joint search by Vietnamese and U.S. experts Sept. 25 to Oct. 5.

He said a second joint search was completed Thursday, but the results of the search, intended to resolve the highest priority cases among the 1,751 missing Americans, were still being analyzed.

U.S. officials have identified 70 high-priority MIA cases involving Americans who were believed to have been captured by the Vietnamese but were not released with other POWs in 1973 after the signing of the Paris Peace Accords.

Of the 23 sets of remains handed over by the Vietnamese, two were believed to be the remains of MIAs in the high-priority category, officials said.

Trout said the search teams spent 10 days in northern Vietnam interviewing Vietnamese villagers and officials who might have information on the high-priority cases.

"Overall we are pleased with the Vietnamese government's unilateral efforts, and it's encouraging that the second joint investigation has also been completed," Trout said.

"It shows that Vietanam is willing to work with us on this humanitarian issue," he said.

Altogether, Vietnam has returned a total of 168 remains identified as American, he said.

In Thursday's 45-minute ceremony at Hanoi's Noi Bai Airport, the remains were placed in aluminum military caskets, each adorned with an American flag. As a 21-man American military contingent stood at attention, the caskets were loaded aboard a U.S. Air Force C-141 jet transport, which later headed toward Hawaii via Guam, Trout said.

The remains were expected to be received in a ceremony at Hickam Field in Honolulu at 9 a.m. Friday.