WASHINGTON (Web Desk) – Pentagon officials warn that millions of defense employees may have to work without pay next week as a budget deadline approaches.

Lawmakers have been scrambling to reach a budget agreement for fiscal year 2016, but partisan disagreements have stalled the process, the UPI reported.

Defense industry members issued an open letter earlier in September voicing their concerns, saying that operating under a continued long-term resolution would threaten their ability to provide the best services for national security interests.

Should Congress fail to reach a compromise, the US government will shut down for the second time in two years. Service members in the US Armed Forces will still have to report to work, however they will not receive paychecks until the shutdown ends.

Furloughed federal workers were awarded back pay following the previous government shutdown in 2013. The Department of Defense said some 1.3 million US troops and 742,000 workers could be affected.

“The uncertainty of the current circumstances puts our workforce in a difficult situation,” Deputy Defense Secretary Robert Work said in a memo. “It could impose hardships on many employees as well the people we serve every day.”

Defense spending has been a topic of interest in budget discussions on Capitol Hill. President Barack Obama has stated he would not accept a budget that “shortchanges readiness”, assuring service members they will get paid despite disagreements.

Spending under the Defense Department’s budget request for fiscal year 2016 would account for 3.1 percent of the US gross-domestic product (GDP).