China’s exports to developing markets have soared, opening indirect routes to the U.S. market that officials in Beijing worry may be closed under pressure from President Trump.

Chinese officials summoned Walmart executives over reports of the retailer pressuring its Chinese suppliers to lower prices to help counteract Trump’s tariffs.

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.