The Trump administration has taken steps to impose levies on Chinese vessels docking at U.S. ports, threatening to shake up global shipping routes and escalate the trade war between the world’s two biggest economies.

Under a plan put forward by the U.S. Trade Representative, all Chinese-built and -owned ships docking in the U.S. would be subject to a fee based on the volume of goods carried. The proposal follows a monthslong investigation ordered by the Biden administration into whether Chinese shipbuilding threatens U.S. national security.

"Ships and shipping are vital to American economic security and the free flow of commerce," U.S. Trade Representative Jamieson Greer said in a statement announcing the new fees, most of which will begin in mid-October.