President Donald Trump’s executive order imposing an across-the-board 10% tariff on all US imports from China went into effect. A month later, he doubled it to 20%.

Trump cited the fentanyl issue as the reason for imposing a 10% tariff on all Chinese imports in early February, on top of any existing duties. He doubled that to 20% earlier this month. He also has cited fentanyl, along with other reasons, for imposing tariffs on Canada and Mexico.

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.