US President Donald Trump floated an 80% tariff on China ahead of negotiations due to begin Saturday as he urged Beijing to do more to open their markets to US goods.

Shipments to the U.S. sank 21% in dollar terms as Trump’s tariffs on most Chinese exports rose to as high as 145%. With Chinese tariffs on U.S. goods at 125%, business between the two biggest economies has grown increasingly uncertain.

China’s exports to the United States fell sharply in April after Donald Trump’s triple-digit tariffs took effect, in another sign of the damage the US president’s trade war is causing