BEIJING, - China's exports of two critical minerals used in weapons, telecommunications and solar cells have plunged over the past three months amid a crackdown on smuggling and transshipment that has involved China's top spy agency.

China's exports of rare earth magnets to the United States in June soared to more than seven times their May level, marking a sharp recovery in the flow of critical minerals used in electric vehicles and wind turbines after a Sino-U.

China's Ministry of State Security says it is cracking down on alleged smuggling of rare earths materials that it says threaten national security.