President Donald Trump's plan to impose tariffs on goods from Mexico, Canada and China is partly aimed at combating the illicit flow of fentanyl into the U.S., where the opioid is blamed for some 70,000 overdose deaths annually.

“A 25% tariff on Canada and Mexico threatens to upend the very supply chains that have made U.S. manufacturing more competitive globally,” he warned, adding that the “ripple effects” of Trump’s tariffs would be especially severe for small and medium-sized manufacturers that may struggle more to find alternative suppliers.

China's government on Sunday denounced the Trump administration's imposition of a long-threatened 10% tariff on Chinese imports while leaving the door open for talks with the U.S. that could avoid a deepening conflict.

Americans consume more illicit drugs per capita than anyone else in the world; about 6% of the U.S. population uses them regularly. One such drug, fentanyl – a synthetic opioid that’s 50 to 100 times more potent than morphine – is the leading reason U.