CAM RANH BAY, Vietnam (Reuters) - Defense Secretary Leon Panetta visited a deep-water Vietnamese port near the contested South China Sea on 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 450 miles 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 on 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, when it served as a key U.S. logistic hub.
Currently, the port only does maintenance on U.S. cargo vessels but not warships. No U.S. warships have visited it since the war, but have called at other Vietnamese ports, U.S. officials said.
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 our ports on the West Coast towards our stations here in the Pacific."
Under the strategy announced in January, the U.S. military aims to be smaller, more flexible and agile. Rather than seeking permanent bases as it has in the past, it is focusing on rotational deployments.
"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.
As part of that, he underscored the importance of moving ahead with ASEAN - the Association of South East Asian Nations - to develop a code of conduct that the countries of the region could abide by in settling disputes and ensuring maritime and navigational rights.
Some ASEAN countries have claims over parts of the South China Sea which has put them at odds with Beijing -- notably Vietnam and the Philippines.
Panetta cited a range of areas in which he was looking to expand cooperation with Vietnam, including high-level exchanges, humanitarian aid and 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.
His Vietnam visit was part of a week-long trip to Asia to explain the new U.S. military strategy. He led a high-level delegation on Saturday to the Shangri-La Dialogue, an annual security conference that draws senior civilian and military leaders from some 30 Pacific nations.
At one session, Singapore announced it had agreed in principle to a U.S. request to forward deploy up to four Littoral Combat Ships to the island state on a rotational basis.
A senior member of Panetta's delegation, General Martin Dempsey, travelled on Sunday to the Philippines which is in talks about a rotational U.S. deployment there.
(Reporting By David Alexander, Editing by Jonathan Thatcher)