The Chinese government on the 22nd added two chemical substances to its export control list for drug precursors, requiring licenses for exports to the United States, Mexico, and Canada. According to a statement from China's Ministry of Commerce, the measure was announced ahead of a planned summit this week in Washington between President Xi Jinping and US President Trump. The Trump administration has repeatedly pressed China to step up measures to curb the flow into the United States of chemicals used to make the synthetic opioid fentanyl.