Defense Secretary Lloyd Austin said the U.S. will stand up to an "increasingly assertive and autocratic” China in the Indo-Pacific region and beyond, calling its activity "disturbing.”

One way to counter China’s military modernization, growing nuclear capabilities and technological advances is to strengthen U.S. alliances in the region, Austin told a security conference in California on Saturday, fresh from a visit to South Korea.

"The activity that we see in the region and other parts of the globe is disturbing,” Austin said at the Reagan National Defense Forum in Simi Valley. China is "acting to develop military capability as fast as it can, but some of the coercive activity we see in the region has us and our partners in the region very concerned,” he said.