Growth in China's exports likely slowed in May despite a lowering of U.S. tariffs on Chinese goods, as the fallout from the still-unresolved trade war and uncertainties in Sino-U.S. ties weighed on shipments.

Each F-35 fighter jet contains roughly 900 pounds of rare earth materials, while submarines can require more than 9,000 pounds, the U.S. Department of Defense has concluded a stark reminder of how deeply integrated these elements have become in the machinery of modern defense.