A bipartisan House measure would provide back pay to Department of Homeland Security employees if the agency partially shuts down Saturday because of a lapse in congressional funding.

Reps. Don Beyer (D-Va.) and Rob Wittman (R-Va.) introduced a bill Tuesday that would compensate Homeland Security workers retroactively once Congress and the president agree on legislation to finance the department’s operations. The agency is set to run out of money on Friday without a deal.

“Today’s bipartisan proposal ensures DHS employees will not lose their pay just because Congress cannot agree on a funding bill,” Beyer said in a joint statement with Wittman on Tuesday. “The men and women of the DHS work hard every day to keep us safe. Now we have to uphold our commitment to them.”

Congress has always agreed to pay federal employees retroactively after past shutdowns, but the delayed compensation is not guaranteed without legislation.

At least two federal-worker unions have voiced support for the bipartisan back-pay measure introduced this week.

In a statement on Tuesday, American Federation of Government Employees president J. David Cox thanked the bill’s sponsors for “recognizing that federal employees are not the cause of any shutdown and should not be punished by being deprived of their pay.”

National Treasury Employees Union president Colleen M. Kelley offered support for the legislation and called on Congress to quickly pass a full-year funding bill for Homeland Security. “It is unthinkable that once again, DHS employees are facing a shutdown,” she said in a statement Tuesday.

The House passed a bill last month that would fund the department while blocking President Obama’s plans for shielding millions of undocumented immigrants from deportation. Senate Republicans have been unable to overcome a Democratic filibuster of the measure, despite four attempts.

On Tuesday, Senate Majority Leader Mitch McConnell (R-Ken.) signaled that he would set up votes to address Homeland Security funding and Obama’s immigration actions separately, giving Congress a chance to pass a “clean” appropriations bill. But Senate Minority Leader Harry Reid (D-Nev.) said he wanted assurances that the House would pass the legislation before rallying support from members of his party.

Obama temporarily halted his immigration plans last week after a federal judge ruled that the actions shouldn’t move forward while being challenged in court by 26 states.

If a shutdown occurs, roughly 85 percent of Homeland Security’s 240,000 employees would remain on the job, either because their duties involve protection of life and property or because their agencies receive significant funding from sources other than Congress, such as through fees.