The self proclaimed most “pro-union president in American history” is under fire from the leader of the most high-profile union in America.

Shawn Fain, the head of the United Auto Workers, has privately expressed his frustration with Joe Biden, wanting the president and other Democratic lawmakers to come out more aggressively in support of his union, which launched a strike Friday against the so-called Big Three automakers.

Fain’s frustration was conveyed by five people familiar with his thinking, who were granted anonymity to describe his position. One of those five described him as “not happy” with the situation. And Fain’s not the only person in Michigan who isn’t thrilled with the way Biden and his team have handled the labor dispute.

Fain was also set to put out remarks, which were exclusively obtained by POLITICO, calling on Biden to get involved.

“We agree with Joe Biden when he says ‘record profits mean record contracts.’ We don’t agree when he says negotiations have broken down. Our national elected negotiators and UAW leadership are hard at work at the bargaining table. Our members and allies are standing strong at the picket lines. Anyone who wants to stand with us can grab a sign and hold the line,” he said, as part of a larger statement.

“The companies and the media want to use fear tactics about how we’re going to wreck the economy. We’re not going to wreck the economy. The truth is we are going to wreck the billionaire economy. Working people are not afraid. You know who’s afraid? The corporate media is afraid. The White House is afraid. The companies are afraid.”

The White House did not immediately respond to a request for comment on the statement.

This is a developing story.