China's state security agency says it is cracking down on alleged smuggling of rare earths minerals that it says threaten national security, just weeks after Beijing and Washington agreed to make it easier for American firms to obtain from China those materials,

Despite a detente on China’s restrictions on the critical manufacturing inputs, shipments remain far below last year’s levels.

China arrests suspects involved in smuggling strategic minerals, and authorities warn of ‘increasingly covert’ tactics to evade detection.