Updated

A Vietnamese military official says a mass grave containing the remains of 35 communist commandos killed during the Tet Offensive was found.

The colonel says officials discovered the grave after being tipped off by a former driver for the U.S.-backed South Vietnam government. He says it took three days of digging to find the bodies.

The Vietnamese soldiers were rounded up and killed by South Vietnamese forces after attacking a U.S. air base in 1968 during the offensive, which is considered a turning point in the Vietnam War.

The discovery comes as the apparent remains of three American soldiers killed during the war are sent back to the U.S. to be identified.

Nearly 1,800 U.S. servicemen are still unaccounted for throughout Southeast Asia since the end of the Vietnam War in 1975.