Vietnam's defense chief told U.S. Defense Secretary Leon Panetta Monday that the communist government will open up three new sites for the search and excavation of troop remains from the war decades ago.

The pledge came during a meeting between Panetta and Vietnamese Defense Minister Phung Quang Thanh. The two military heads also exchanged artifacts from the war – a Vietnamese soldier's diary, and personal letters written by a U.S. soldier – taken by troops from both sides during the Vietnam War.

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

The defense secretary visited 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 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.