China tightened its rare earth export controls on Thursday, expanding restrictions on processing technology and spelling out its intention to limit exports to overseas defence and semiconductor users.

The announcement from the Ministry of Commerce clarifies and expands sweeping controls announced in April that caused shortages around the world before a series of deals with Europe and the US eased but did not eliminate the supply crunch.

The controls are a major bargaining chip for China in its trade talks with the United States, and the tightening comes weeks ahead of a face-to-face meeting between Presidents Donald Trump and Xi Jinping in South Korea.

"From a geostrategic perspective, this helps with increasing leverage for Beijing ahead of the anticipated Trump-Xi summit in Korea late

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