The CEO of the world’s largest cobalt mining company issued a stern warning to U.S. and European automakers that they had better get their acts together to secure supplies of this precious metal or else risk becoming dependent on China for batteries to power their electric vehicles.

Glencore chief executive Ivan Glasenberg told the FT Future of the Car Summit that China had “tied up” lots of cobalt supplies in the DRC and if they want to avoid similar disruptions to their supply chains as they’re now experiencing due to chip shortages, they had better do something about securing supplies of cobalt. Otherwise, he said, they could become entirely dependent on China for a critical part of their new energy vehicle supply chains.