Defense Secretary Leon Panetta ruled out troop cuts in Asia as part of US belt-tightening as he arrived in Japan on Monday, flagging concerns about a “reckless” North Korea and Chinese military assertiveness. Panetta, on his first trip to Asia since taking over the Pentagon's top job in July, has been assuring allies in the region that the US military will maintain a strong posture in the Pacific despite looming defence spending cuts at home. “We are not anticipating any cutbacks in this region. If anything we are going to strengthen our presence in the Pacific,” Panetta, a former CIA director, told a gathering of US and Japanese forces at Yokota Air Base outside Tokyo. In an opinion piece he published in a newspaper in Indonesia – his first stop on his Asia tour – Panetta acknowledged US allies have expressed concern “that America may not follow through on our commitments in this region.” Questions about a potential decline in US military power in the Pacific due to America's fiscal woes come as China's military invests heavily in new technologies, including its aircraft carrier programme, stealth fighter jet and an anti-ship ballistic missile. But Panetta said the complete US military withdrawal from Iraq this year and the gradual drawdown in Afghanistan would enable the United States to shift more attention to the Asia-Pacific region. They would also allow for more focus on concerns like the threat posed by cyber warfare technologies. “We have the opportunity now to be able to focus on those challenges,” Panetta told the gathering. “Most importantly, we have the opportunity to strengthen our presence in the Pacific. And we will.” Panetta's stop in Japan follows a meeting in Indonesia with defence mnisters from the 10-member Association of South East Asian Nations. After visiting Japan, he completes his week-long visit to Asia in South Korea. In an opinion piece Panetta wrote for Japan's Yomiuri newspaper, the defence chief noted that China was rapidly modernising its military “but with a troubling lack of transparency, coupled with increasingly assertive activity in the East and South China Seas”.