China has reiterated it could take “necessary countermeasures" after U.S. President Donald Trump decided to impose a 10% tariff on China for allegedly doing too little to stem the production of precursor chemicals for the drug fentanyl.

Trump has long proposed raising tariffs—or taxes on imported goods that the businesses importing them pay the U.S. government—before the election, and said in November he’ll impose a 25% tariff rate on all imports from Mexico and Canada on the first day of his presidency and will impose an additional 10% tariff rate on all imports from China on top of other tariffs.