WASHINGTON—China is reportedly looking into curbing the export of rare earth minerals to the United States, which may become a new source of friction between the two countries. China’s Ministry of Industry and Information Technology in January proposed draft controls on the production and export of rare earth minerals and provided 30 days for public comment. During the comment period, industry executives were asked to assess how U.S. and European companies could be affected if Beijing decided to cut rare earth exports during a bilateral dispute, the Financial Times reported, citing people involved in the discussions. “The government wants to know if the U.S. may have trouble making F-35 fighter jets if China imposes an export ban,” a Chinese government adviser told the Financial Times. Industry executives were also asked to comment on how quickly the United States could secure rare earths from alternative suppliers or increase its production capacity. …