The Trump administration has formally rejected China’s demand that it be treated as a “market economy” under global trading rules, a move likely to heighten tensions between the world’s two largest economies, The Wall Street Journal reported.

The U.S. submitted its decision to the World Trade Organization in Geneva in mid-November and made it public on Thursday. Trump aides have long signaled their stance on the issue, but the filing marks the first time the U.S. government has publicly declared its position and explained its reasoning.

The fight’s stakes are high. The trading partners of a country branded a “nonmarket economy” have wider discretion to impose higher duties on its exports on the theory that distortions from state intervention give its producers unfair advantages. Economists have estimated that the decisions by the U.S. and European Union to treat China as a nonmarket economy have cost Chinese producers billions of dollars in exports, with some of their goods facing tariffs well above 100%.