BRUSSELS, Belgium — The United States, the European Union and Japan filed complaints Tuesday with the World Trade Organization charging that China is limiting its export of rare earths, minerals that are vital to the production of technology components. China has a stranglehold on the global supply of 17 rare earth minerals that are essential for making high-tech goods including hybrid cars, weapons, flat-screen TVs, mobile phones, mercury-vapour lights, and camera lenses. But China has cut its export quotas of these minerals over the past several years to cope with growing demand at home, though the government also cites environmental concerns as the reason for the restrictions. U.S. industry officials suggest it is an unfair trade practice, against rules established by the WTO, a group that includes China as a member.