China has appointed a new trade negotiator in the midst of its tariff fight with the United States as the world’s two largest economies steadily increase tariffs on each other’s goods.

President Donald Trump‘s administration has hiked tariffs on Chinese imports to the U.S. by up to 245%, as per a fact sheet released by the White House on Apr. 15. Trump signed an executive order launching an investigation into the national security risks posed by American reliance on imported critical minerals and their derivatives.

President Donald Trump signed an executive order on Tuesday that launched a national security investigation into the U.S. reliance on imports of critical minerals, after China suspended exports of certain rare earth metals and magnets.