President Obama arrived in Tokyo Wednesday where he is kick starting the first part of a trip to Asia aimed in part at renewing the U.S.'s security commitment to the region.
Ahead of his arrival in Japan he confirmed that America's mutual security treaty with Japan applies to the islands at the center of a territorial dispute between China and Japan.
"The policy of the United States is clear," he said in a written response to questions published in Japan's Yomiuri newspaper before his arrival in Tokyo at the start of a four-country Asia tour that will also see the president travel to South Korea, the Philippines and Malaysia, but not China, the regional superpower.
"The Senkaku islands are administered by Japan" and therefore fall under the U.S.-Japan treaty, he wrote. "And we oppose any unilateral attempts to undermine Japan's administration of these islands."
During a recent Asian tour, Defense Secretary Chuck Hagel pledged to deploy two more ballistic missile defense destroyers in Japan by 2017 in a bid to allay Japan's worries over a territorial dispute with China and missile launches by North Korea.
Hagel also rebuked Beijing for escalating the territorial dispute, which is over Japanese-controlled islands in the East China Sea that Japan calls the Senkaku islands and China calls the Diaoyu.
The U.S. is obligated to protect Japan from attack, but has sought to avoid taking a stand on sovereignty over the islands.
Tokyo is hoping for more in the way of confidence building, said Hitoshi Tanaka, chairman of the Institute for International Strategy in Tokyo.
"We would like to see the president make a strong, clear statement about the Senkaku," Tanaka said. "There is a need for Japan and the U.S. to work to improve the security situation in East Asia."
Obama's trip to Japan will be the first state visit to America's closest ally in Asia by a U.S. president since Bill and Hillary Clinton came in 1996. He will be the first sitting U.S. president to visit Malaysia since Lyndon Johnson in 1966. Allies South Korea and the Philippines, the two other stops on his agenda, are also keen to shore up security ties.
Economic ties will also be a major focus of the trip with China's fast-growing economy likely to feature heavily.
In a separate development, Philippine police armed with truncheon, shields and water hose clashed Wednesday with more than 100 left-wing activists who rallied at the U.S. Embassy in Manila to oppose a visit by Obama and a looming pact that will increase the American military presence in the Philippines.
Hjelmgaard reported from London; Jackler from McLean, Va.; Contributing: Associated Press