U.S. Regains Favor in Parts of Asia BEIJINGâ€”The Obama administration's talks with China this week won few new commitments from Beijing on global security challenges, particularly when it comes to looming showdowns with North Korea and Iran. But Beijing's increasing diplomatic and military assertiveness is unnerving its Asian neighbors in ways that could bolster the U.S.'s strategic position in the region. Fears that China is siding with Pyongyang over the North's alleged sinking of a South Korean naval vessel in March has rattled South Korea's and Japan's governments and re-energized their commitments to military alliances with the U.S., according to officials from both countries. Japanese Prime Minister Yukio Hatoyama publicly cited the North Korean threat last week in recommitting Tokyo to stationing U.S. Marines on the island of Okinawa. Further afield, countries like Malaysia and Vietnam have also been seeking closer ties to the U.S. in recent months, according to American and Asian diplomats. These countries are quietly voicing fears about China's expanding military and economic power. Analysts say that the more China has sought to assert its regional authority, the more many Asian leaders have pressed Washington to maintainâ€”if not increaseâ€”its military and diplomatic presence. The U.S. "should be sending China thank you notes" for its handling of the North Korea issue, said Ralph Cossa, a former U.S. Air Force colonel who heads the Pacific Forum CSIS, a Hawaii-based think tank. China "very much played into the hands of both the U.S. and Hatoyama's interests," he said. South Korea's strong ties with Beijing have been tested by China's reaction to Pyongyang's alleged torpedoing of the South Korean vessel, the Cheonan. China waited nearly a month to send condolences to South Korea for the loss of 46 of its servicemen. Chinese President Hu Jintao rankled Seoul by secretly hosting North Korean leader Kim Jong Il this month to a string of meetings in Beijing. South Korea President Lee Myung-bak had visited China just days earlier and hadn't been told of Mr. Kim's visit, according to South Korea officials. Last week, South Korea made public its investigation into the Cheonan's sinking and formally charged North Korea with launching the torpedo. But China's government continues to express skepticism toward the results of Seoul's probe, which included input from American, Australian, and Swedish investigators. North Korea has denied any involvement in the attack. China has "taken note of the result of the South Korean investigation," Foreign Ministry spokeswoman Jiang Yu said Tuesday. "We have also taken note of the DPRK's response," she added, referring to the North's formal name: the Democratic People's Republic of Korea. Chinese scholars broadly reject criticism of Beijing's handling of relations with Seoul. Shen Dingli, a professor of international relations at Fudan University in Shanghai, says China needs to maintain its neutrality over the Cheonan incident because it isn't sure the outcome of the investigation is accurate. He says Seoul could have fabricated the investigation's results to frame Pyongyang. "The chance of fabrication might be 1%. The chance that this is real is maybe 99%. But this is the difference between peace and war. So we need to be 100% certain," said Mr. Shen. "From the first day, South Korea should have invited China and North Korea to participate in this investigation," he said. Beijing's public paralysis on the Cheonan feud may flow from what it sees as a lack of good options. It doesn't want to position itself on the wrong side of the international community, but it also doesn't want to facilitate any action that could destabilize the North Korean government and lead to chaos that could spill into its territory and, potentially, lead to control of the North by Seoul, putting a military ally of the U.S. directly on China's border. Mr. Shen says China will likely to remain loyal to North Korea for a simple strategic reason. "We need North Korea to check and balance the American military presence in South Korea and Japan," he says, just in case, for example, there were a conflict with the U.S. over Taiwan. Recent tensions between Beijing and Tokyo offer another stark example of how China's growing assertiveness has rattled the region. Mr. Hatoyama entered office last year pursing a policy line very much in China's interest: a more "equal" relationship between Tokyo and Washington and the removal of American troops from Okinawa. Japan's leader has also repeatedly discussed the idea of creating an "East Asia" community modeled after the European Community. Still, China-Japan relations have soured significantly in recent months. In early May, Japan filed a formal protest to Beijing after a Chinese ship chased a Japanese Coast Guard vessel that Tokyo says was conducting marine surveys within a Japanese zone. Japan filed another protest a month earlier after a Chinese helicopter buzzed a Japanese ship sailing near the location of Chinese military exercises. On May 15, Japanese and Chinese diplomats publicly sparred at a meeting in South Korea, after Tokyo's Foreign Minister Katsuya Okada pressed Beijing to shrink, or at least not increase, its nuclear-weapons arsenal. Chinese Foreign Minister Yang Jiechi countered that Beijing's nuclear strategy was clear and its position on disarmament widely recognized. But Mr. Okada repeated his remarks at a trilateral meeting with South Korea's chief diplomat. According to people familiar with the exchange, Mr. Yang became so upset that he started yelling at Mr. Okada. A Chinese foreign ministry spokesman later called Mr. Okada's remarks "irresponsible." Mr. Okada said such accusations were groundless. "The Chinese side stated various things during our exchange, but I didn't hear them say once they weren't building up" their nuclear arsenal, Mr. Okada said. China's growing confidence is also raising fears in Southeast Asia, and stimulating a new courtship of the U.S. Muslim-majority Malaysia has often had rocky relations with Washington in recent decades. Former Prime Minister Mahathir Mohammed openly sought to challenge U.S. economic policies during the 1997 Asian financial crisis. And Kuala Lumpur has regularly attacked American foreign policy in the Islamic world. Under new Prime Minister Najib Razak, however, Malaysia has increasingly sought to reorient itself toward the U.S., according to American and Malaysian officials. The two sides have been discussing the possibility of Kuala Lumpur's sending a reconstruction team to Afghanistan, which would make Malaysia one of the few Muslim countries to deploy troops. And Mr. Razak's government just passed through a draconian law regulating the export of dual-use technologies to countries like Iran. American officials have regularly complained that Malaysia has served as one of the primary conduits for military equipment entering Iran. Malaysian officials have said in interview that its foreign policy shift is largely being driven by its fear of China's growing power. "We can't afford right now not to be on good terms with the U.S," said a senior Malaysian official. "It made no sense for us to be in conflict" with Washington. â€”Sue Feng contributed to this article.