Some European auto parts plants have suspended output and German carmaker BMW warned its supplier network was affected by shortages of rare earths, as concerns about the damage from China's restrictions on critical mineral exports deepen.

Sefcovic’s comments echo concerns raised by other government officials including those in the Trump administration, which has accused China of breaking a deal reached in Geneva last month to, among other things, lower barriers for exports of rare earth materials.

Police officers, customs officials and spies are reinforcing China’s embargo on the critical minerals that it overwhelmingly controls.