Transportation Secretary Sean Duffy threatened penalties for air traffic controllers who failed to show up for work for during the government shutdown.

At Chicago’s O’Hare International Airport on Tuesday, a reporter asked Duffy about President Donald Trump’s plans to dock the pay of air traffic controllers who are calling in sick during the government shutdown.

“My concern is, for those air traffic controllers who, before they missed a paycheck, and were in the shutdown, they decided on a continual basis not to show up for work,” Duffy replied. “They don’t know how long the shutdown was going to be, they hadn’t missed a pay period, and they didn’t come to work.”

“I’m concerned about their dedication. I’m concerned about their patriotism,” Duffy later added of the employees who skipped work.

Noting that the Trump administration hasn’t “made a decision” about specific penalties, Duffy allowed that he was “trying to bring more air traffic controllers in,” but warned, “if we have controllers who systemically weren’t doing their job, we will take action.”

Transportation Secretary Sean Duffy previously praised the air traffic controllers who have worked throughout the shutdown.

via Associated Press

On Monday, Trump scolded air traffic controllers in a Truth Social post, telling them that he was “NOT HAPPY” about those who missed work and warned that they “will be quickly replaced by true Patriots.”

“All Air Traffic Controllers must get back to work, NOW!!! Anyone who doesn’t will be substantially ‘docked,’” Trump wrote before noting that he would recommend a $10,000 bonus for any workers who “didn’t take ANY TIME OFF for the ‘Democrat Shutdown Hoax.’”

Trump added, “You didn’t step up to help the U.S.A. against the FAKE DEMOCRAT ATTACK that was only meant to hurt our Country. You will have a negative mark, at least in my mind, against your record.”

Last month, Duffy threatened to fire air traffic controllers who missed work, citing chaotic air disruptions.

“If we have a continual small subset of controllers that don’t show up to work, and they’re the problem children ... if we have some on our staff that aren’t dedicated like we need, we’re going to let them go,” Duffy said on Fox Business. “I can’t have people not showing up for work.”

During the ongoing government shutdown, air traffic controllers have faced financial stress while being required to work without pay. The staffing shortages across the nation have led to major flight delays and cancellations.

The GOP-controlled House is set to vote Wednesday on a spending package to end the longest government shutdown in U.S. history.