In a surprising reversal of the United States’ years-long technology restrictions on China, President Donald Trump last month allowed Nvidia to resume sales of a key AI chip designed specifically for the Chinese market.

Senate Democrats are urging Trump to halt his plan allowing Nvidia and AMD to sell AI chips to China in exchange for a 15% revenue share with the U.S. The lawmakers warned in a letter that the policy could strengthen China’s AI sector and undermine U.

The move could open the door to China securing more advanced computing power from the U.S. even as the two countries battled for technology supremacy, critics said.