U.S. trading partners are weighing responses after President Donald Trump’s latest action on tariffs sparked a stock market selloff Monday. The White House sent letters yesterday to about a dozen countries laying out the rates at which imports would be taxed—ranging from 25% to 40%—if no other trade agreements are reached.

China warned the Trump administration on Tuesday against reigniting trade tension by restoring tariffs on its goods next month, and threatened to retaliate against nations that strike deals with the United States to cut China out of supply chains.

The US president appears to be taking direct aim at the world’s biggest metals processor by targeting exports all along the supply chain.