A group of labor unions led by the United Steelworkers slammed the Trump administration for suspending port fees on Chinese ships that workers argued would bring about a revival in the once-dominant domestic shipbuilding industry.

The unions expressed "strong disappointment” with the administration’s decision and said it would have negative consequences in the nation’s attempt to restore the U.S. maritime sector, according to a letter sent to U.S. Trade Representative Jamieson Greer. The letter, also signed by the International Association of Machinists, International Brotherhood of Electrical Workers and International Brotherhood of Boilermakers, said the decision will allow China to continue "predatory behavior.”

The strong comments come a week after President Donald Trump touted a trade truce between the world’s largest economies, assuring Americans that the Chinese would buy more agricultural goods and roll back export controls on rare-earth minerals that threatened to undermine U.S. national security. But the pushback also shows that the deal came at the expense of some blue-collar workers, which could hurt the president during next year’s midterm elections in key battlegrounds.