U.S. Defense Secretary Leon Panetta Sunday visited a major base used by American forces during the Vietnam War.

Panetta is the highest-ranking U.S. official to visit the former U.S. air force and naval base at Cam Ranh Bay since the war ended in 1975.

Officials said the defense secretary would visit an American naval cargo ship currently at the port, the Richard E. Byrd, which moves cargo for the U.S. naval fleet with a mostly civilian crew.

Panetta's visit to Vietnam follows a speech on Saturday at a security forum in Singapore, in which he said the U.S. Navy would shift the majority of its ships to the Pacific by 2020 as part of a strategic focus on Asia.

He is on a week-long tour of the Asia-Pacific region, which will also take him to India.