Over 70 Democrats on Tuesday urged US President Donald Trump to keep Chinese carmakers out of America, warning of “irreversible” consequences, just weeks ahead of his high-stakes trip to Beijing to meet with China’s President Xi Jinping.

“We must not cede the American auto industry to a strategic competitor intent on global dominance,” a letter, signed by 73 House Democrats led by US Representative Debbie Dingell, said. “The consequences for American workers, our supply chains, our national security, and our communities would be profound and irreversible.”

Ahead of the trip, Democrats warned that “any effort to lower barriers for Chinese automobiles or otherwise facilitate their entry into the US market would pose a direct threat to American manufacturing, workers, and national security,” adding that it was a firm and non-negotiable priority.

Among the letter’s signatories was Ro Khanna, the top Democrat on the House Select Committee on the Communist Party.

Trump has expressed openness to Chinese carmakers entering the US since returning to office, as long as they build their factories in America and hire local workers.