U.S. Defense Secretary Leon Panetta visited a deep-water Vietnamese port near the contested South China Sea Sunday, calling access to such harbors critical as the U.S. shifts 60 percent of its warships to the Asia-Pacific by 2020. Panetta flew to Cam Ranh Bay, one of Asia’s finest deep-water harbors located about 720 kilometers south of China, just a day after he spelled out details of a new U.S. military strategy that calls for a shift in focus to the Pacific after a decade of conflict in Afghanistan and Iraq. While U.S. officials insisted the visit had nothing to do with China, Panetta’s appearance was likely to heighten concerns among some Chinese officials who see the shift as an attempt to fence in the country and frustrate Beijing’s territorial claims, especially in the South China Sea. Chinese Lieutenant General Ren Haiquan noted the U.S. decision to increase the number of warships in the Pacific during remarks at the Shangri-La Dialogue security forum in Singapore Sunday. “First, we should not treat this as a disaster,” Ren said. “I believe that this is the United States’ response to its own national interests, its fiscal difficulties and global security developments,” he said in comments reported by Hong Kong’s Phoenix Television. Panetta, who toured a Navy supply ship undergoing repairs, was the most senior U.S. official to visit Cam Ranh Bay since the Vietnam War. Currently, the port only does maintenance on U.S. cargo vessel, but no U.S. warships. Speaking from the deck of the USNS Richard E. Byrd, Panetta said his visit was symbolic of how far the two countries have come since they normalized relations 17 years ago and that partnerships with countries like Vietnam were critical to the new U.S. military strategy. “We are rebalancing our forces to the Asia-Pacific ... so that in the future, 60 percent of our forces will be located in this region,” he said. “For that reason, it will be particularly important to be able to ... work with partners like Vietnam to be able to use harbors like this as we move our ships from ports on the West Coast toward our stations here in the Pacific.” Under the strategy announced in January, the U.S. military aims to be smaller, more flexible and agile. “We are stressing our effort to try to develop partnerships with countries in this region, to develop their capabilities so that they can better defend and secure themselves,” he said. Panetta cited a range of areas in which he was looking to expand cooperation with Vietnam, including humanitarian aid, disaster relief and peacekeeping operations. “In particular we want to work with Vietnam on critical maritime issues, including a code of conduct focusing on the South China Sea and also working to improve freedom of navigation in our oceans,” he said.