July 7 (Reuters) - China's export restrictions on rare earths brought parts of the global auto supply chain to a halt and U.S. President Donald Trump to the negotiating table. But at home, they're a big headache for companies already struggling with a slow economy.

China’s exports of rare-earth products jumped in June, pointing to a potential pickup in magnet supplies after government-imposed curbs that proved to be Beijing’s most powerful weapon in its trade war with the Trump administration.

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