China's yuan slipped against the dollar while falling to a near two-year low versus its major trading partners on Friday, as U.S. President Donald Trump and Chinese leader Xi Jinping held a much-anticipated call but left key issues that have stoked tensions between the world's two largest economies unresolved.

China views its rare earths as a national security issue, not a trade one, and that’s why Beijing is unlikely to loosen controls any time soon, experts say.

President Donald Trump and Chinese President Xi Jinping discussed trade negotiations between Washington and Beijing Thursday over the phone.