(CNN) - The U.S. government is facing a lawsuit for forcing “essential” personnel to work without pay during the partial shutdown, based on claims the practice violates federal labor law.
The American Federation of Government Employees filed suit Monday on behalf of the approximately 420,000 federal employees who are working without pay following the Dec. 22 government shutdown.
The union claims the government is violating the Fair Labor Standards Act, and in a statement, its president called the requirement “inhumane.”
"Federal workers are going to be penalized for not paying their bills on time - when we just want to go back to work,” said Loreen Targos, a physical scientist for the EPA.
President Donald Trump claims federal workers have told him to keep the government shut down until Congress agrees to fund a border wall between the U.S. and Mexico. He wants $5 billion for the project.
"Many of those workers have said to me and communicated: ‘Stay out until you get the funding for the wall.’ These federal workers want the wall,” Trump said.
Democratic senators Nancy Pelosi, of California, and Chuck Schumer, of New York, issued a statement Monday, saying “the president is using the government shutdown to try to force an expensive and ineffective wall upon the American people.”
Efforts to compromise on a lower border security budget have failed, despite allies like Sen. Lindsey Graham (R-SC) saying Trump is “receptive to making a deal if it achieves his goals of securing our border.”
"It's not going to be open until we have a wall, a fence, whatever they'd like to call it,” said Trump, while speaking to reporters on Christmas Day.
In addition to the “essential” federal employees working without pay, about 380,000 employees will be furloughed due to the shutdown.
About 25 percent of the government, including correctional officers, border patrol agents and transportation security officers, has been affected by the shutdown.
As of Monday night, the White House had not commented on the lawsuit.