China overtook Japan as Asia's biggest arms spender in 2006 as global military expenditures grew 3.5 percent to US$1.2 trillion, a Swedish research institute said Monday. The United States remained by far the world's biggest military spender last year, devoting about US$528 billion on arms, ahead of Britain and France, the Stockholm International Peace Research Institute said. "The large increase in the USA's military spending is to a great extent due to the costly military operations in Afghanistan and Iraq," SIPRI said in its annual report. China's growing military expenditures reached nearly US$50 billion, making it the fourth biggest arms spender in the world, SIPRI said in its annual report. Japan was fifth with US$43.7 billion.