Signs are emerging that a showdown over hegemony is growing in the Asia-Pacific region between the U.S. and China.

U.S. Defense Secretary Leon Panetta stressed on Sunday the need for stronger cooperation with the Vietnamese military in a visit to Vietnam’s Cam Rahn Bay, which used to house a key U.S. military base during the Vietnam War.

Previously, Panetta announced a plan to deploy eight more cutting-edge naval vessels to the Asia-Pacific region at this year’s Asia Security Summit known as the Shangri-La Dialogue in Singapore.

In regards to a territorial dispute between China and the Philippines in the South China Sea, he urged Beijing to respect regional rules.

His remarks have invited resistance from Chinese military officials who are vowing not to sit back and watch.