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.’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.”

Read More: Reviving U.S. Shipbuilding: Is It Realistic?

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.

“By suspending 301 remedies for one year, the U.S. government is introducing uncertainty at the very moment when confidence and long-term planning are most essential,” the unions wrote in the letter. “Suspending implementation of the responsive actions under the Section 301 investigation will continue to give China a free pass.”

On November 6, the office of the U.S. Trade Representative opened an usually short comment period on terms of a deal struck between Trump and his Chinese counterpart Xi Jinping. 

The unions’ letter was submitted November 7, before the deadline at 5 p.m. Eastern.

Trump’s plan would pause tariffs on imports of ship-to-shore cranes and chassis from China, in addition to a suspension of fees levied on Chinese-built and -operated merchant ships calling at American ports. China agreed to halt retaliatory measures in return for U.S. action, according to a fact sheet released by the White House after Trump and Xi met last week.

The pause would begin November 10 and is effectively a yearlong pledge not to invoke tariffs or other penalties stemming from a U.S. probe into China’s actions in the maritime, logistics, and shipbuilding sectors. 

The investigation under Section 301 of the Trade Act of 1974 began during the Biden administration, at the request of five labor unions representing U.S. steelworkers and shipbuilders, including those that signed the November 7 letter.

Trump has looked to counter China’s growing influence on the shipbuilding sector with the probe as well as with deals with Japan and South Korea to bolster alternatives. 

The push to revive U.S. shipbuilding capacity has received broad support from Republicans and Democrats in Congress, and bipartisan legislation complimentary to the policy aimed at China’s maritime sector was the subject of a Senate hearing just last week. The measure is also supported by much of the domestic maritime industry.