U.S. Transportation Security Administration staff have resumed their paychecks, but many airports still face staffing shortages.

The U.S. Transportation Security Administration (TSA) staff have received their paychecks again.

Due to a funding stalemate, most TSA employees received two lump-sum back pay payments in full on Monday after more than five weeks of unpaid work. Union officials and a spokesperson from the U.S. Department of Homeland Security confirmed the news. The spokesperson said the Department of Homeland Security is working to expedite the payment of the remaining half of the back wages.

Payroll resumed on Monday. This followed an executive order signed by U.S. President Trump late last week instructing federal officials to pay TSA employees. Over the past month, TSA staff at airports in places such as Houston, Atlanta, and New York have been absent in large numbers, forcing travelers to endure queues that lasted as long as several hours. Union officials said many have had to take on part-time jobs to cover everyday expenses.

According to the Department of Homeland Security, airport absenteeism continued throughout the entire weekend. On Sunday, about 10.6% of TSA personnel were absent on leave, down from a peak of about 12.4% on Friday.

The Department of Homeland Security said that Baltimore/Washington International Thurgood Marshall Airport was the hardest-hit on Sunday, with more than 38% of staff absent. Airports in Houston, New Orleans, and Atlanta also saw more than one-third of personnel absent.

Trump’s executive order covers the back pay owed to these employees—wages that have been withheld since the Department of Homeland Security funding lapsed on February 14. So far, Congress has not reached an agreement on the department’s funding, and it is currently in a two-week recess.

“Calling it anything less than our utter disgust and disappointment in elected officials is understating it,” said the chair of the TSA employees’ union, Heidrick Thomas. “Congress has to come back to Washington to resolve this crisis, and stop putting politics ahead of the public and vacations ahead of values.”

According to the industry association Airlines for America, which represents major U.S. airlines, during the government shutdown, the absenteeism rate of some airport TSA staff had reached 40% to 50%. The association said that during the same period, attacks targeting TSA personnel increased fivefold.

The TSA’s staffing shortage may continue. A Department of Homeland Security spokesperson said that unpaid work during the shutdown has caused more than 500 people to leave the agency.