The U.S., where fentanyl abuse has been a major cause of death, has pushed China for deeper law enforcement cooperation, including tackling illicit finance, arrests of rogue chemists and raids of labs involved in the production of precursors.

Fresh tariffs on Chinese imports put U.S. retailers in a tough spot. Raising prices risks the ire of President Trump and American consumers, but getting suppliers to bear the burden isn’t simple either—and in Walmart's case,

The Chinese government announced the tariffs last week, shortly after President Trump raised tariffs on Chinese products for the second time since he took office in January. The Chinese tariffs will include a levy of 15 percent on U.S. products like chicken, wheat and corn, as well as 10 percent on products like soybeans, pork, beef and fruit.