Cambodian Prime Minister Hun Manet held talks with US Defense Secretary Lloyd Austin on Tuesday. The meeting is seen as a bid by Washington to counter China's increasing military influence in the Southeast Asian country.
Austin's visit to Cambodia comes two days after he attended the Shangri-La Dialogue security summit in Singapore.
Hun Manet said Austin told him the United States will strengthen and expand cooperation with Cambodia, especially in the defense sphere. He also said he asked Austin to restart military cooperation, including holding joint drills and officer cadet exchanges. Both Austin and Hun Manet graduated from the US Military Academy at West Point.
Austin earlier met Cambodian Senate President Hun Sen, who was the country's longest serving prime minister.
Hun Sen said Austin told him Washington is working to improve ties with Cambodia. He also said he asked Austin not to involve Cambodia in what he called the US's "geopolitical strategic battle".
The US is believed to be wary of Cambodia's recent military ties with China. The two countries' latest annual joint military exercises ended last week.
Washington and its allies have become increasingly concerned that Cambodia's Ream Naval Base near the South China Sea is developing into a new strategic outpost for the Chinese navy.