A former top Chinese trade adviser warned that export trade controls put in place by China are “just a beginning” of their economic plans, ahead of a scheduled visit to the country from Treasury Department Secretary Janet Yellen. 

Former Vice Minister of Commerce Wei Jianguo told China Daily, a Chinese government-run outlet, Wednesday that Beijing is prepared to place additional trade restrictions on metals used in semiconductors if the United States hits China with tougher technology restrictions. 

“This is just the beginning of China’s countermeasures, and China’s tool box has many more types of measures available,” Wei said. “If the high-tech restrictions on China become tougher in the future, China’s countermeasures will also escalate.”

The Chinese Commerce Ministry announced Monday that starting Aug. 1, it will establish limits on the exportation of two rare metals — germanium and gallium — needed for producing semiconductors and electric vehicles. The agency said the exports will only be permitted if the exporters receive licenses from the ministry. 

An editorial in China Daily after the announcement slammed the Netherlands for the export controls it has placed on semiconductor components. China is the leader in the world production of both materials. 

Wei said Wednesday that the decision to place export limits came after significant consideration and will inflict pain on other countries. 

Reuters reported that analysts have said the action is a step in the ongoing battle over technology between the U.S. and China, and it raised worries that additional restrictions could be placed on rare earth exports. 

Yellen plans to visit Beijing on Thursday as U.S. officials try to reduce tensions that have been high with China for months.

Secretary of State Antony Blinken met with top Chinese officials in Beijing last month to hold diplomatic discussions.