Unlike opium, nitazenes and other synthetic opioids can be produced anywhere in the world using precursor chemicals that are often uncontrolled.

China, the U.S.'s third-largest trade partner, has restricted exports of the strategic metals tungsten, bismuth, indium, molybdenum and tellurium.

China unveiled multiple countermeasures on Tuesday, immediately after new U.S. tariffs on its imports took effect. This marks the latest development in an escalating trade dispute that began with ...