A draft memo from the Office of Management and Budget (OMB) is raising the possibility that furloughed federal workers may not be entitled to back pay from their time off during the government shutdown.

An administration confirmed to The Hill that the memo, which was first reported by Axios, hinges on an aggressive interpretation of the Government Employee Fair Treatment Act of 2019, which President Trump signed during the last government shutdown.

The OMB memo argues the law does not automatically guarantee that all furloughed employees are guaranteed back pay. It cites a line in the amended version of the law, which states that furloughed workers will receive back pay “subject to the enactment of appropriations Acts ending the lapse.”

Attempts to withhold back pay for furloughed workers would face legal challenges from employees’ unions. It would also be at odds with guidance issued by the Office of Personnel Management (OPM) last month ahead of the ongoing government shutdown.

The OPM guidance features answers to frequently asked questions, including whether furloughed employees will get paid.

“Yes. After the lapse in appropriations has ended, employees who were furloughed as the result of the lapse will receive retroactive pay for those furlough periods,” the guidance states. “Retroactive pay will be provided on the earliest date possible after the lapse ends, regardless of scheduled pay dates.”

Sen. Patty Murray (D-Wash.), who serves as the vice chair of the Senate Appropriations Committee, pushed back on the OMB memo as a “baseless attempt to try and scare & intimidate workers by an administration run by crooks and cowards.”

“The letter of the law is as plain as can be—federal workers, including furloughed workers, are entitled to their back pay following a shutdown,” Murray said.

Everett Kelley, president of the American Federation of Government Employees, called the OMB memo an “obvious misinterpretation of the law.”

“As we’ve said before, the livelihoods of the patriotic Americans serving their country in the federal government are not bargaining chips in a political game,” Kelley said in a statement. “It’s long past time for these attacks on federal employees to stop and for Congress to come together, resolve their differences, and end this shutdown.”

The memo on back pay is the latest example of how the Trump administration is threatening action against federal workers amid the shutdown.

White House officials have for days warned of widespread layoffs across the government if the shutdown continues, even though past shutdowns have led to furloughs but not firings.

“We don’t want to see people laid off. But unfortunately, if this shutdown continues, layoffs are going to be an unfortunate consequence of that,” White House press secretary Karoline Leavitt told reporters Monday.

The Senate on Monday pushed the government shutdown to the one-week mark as Democrats blocked the GOP’s “clean” stopgap funding bill from advancing for a fifth time.

Democrats are demanding the stopgap bill include an extension of Affordable Care Act (ACA) premium tax credits that are slated to expire at the end of the year.

Updated at 10:37 a.m. EDT