Hanoi - Vietnamese authorities turned over four sets of remains believed to be of US soldiers killed decades ago, at a repatriation ceremony Tuesday at Hanoi's international airport.

Dao Xuan Kinh, director of Vietnam's Office for Seeking Missing Persons, said they were believed to be of US pilots shot down over the country between 1965 and
1972.

"We found these four sets of remains in four different provinces in northern Vietnam," Kinh said.

The remains were put on a US Air Force aircraft for transport back to the United States and forensic testing.

They were recovered after extensive attempts to locate crash sites in northern Vietnam, based on information from the US military.

US and Vietnamese officials declined to release details regarding the potential identities, citing interest of the families.

Kinh said the Vietnamese government and citizens regarded locating the remains of missing US soldiers to be a humanitarian effort.

"I am very pleased with the ongoing relationship that we have had," said Lt Col Todd Emoto of the US Joint POW/MIA Accounting Command.

More than 58,000 US soldiers were killed in Vietnam, and 1,981 were unaccounted for at the war's end in 1973.

So far, Vietnam has excavated and transferred 857 sets of remains to the US government, 634 of which were successfully identified, Kinh said.

Some 3 million Vietnamese are estimated to have died in the war, and about 1 million are unaccounted for. The government continues to unearth their remains, including a recent discovery of 600 bodies in a mass grave on the island of Phu Quoc in southern Vietnam, which was used as a prison camp by the US military. (dpa)