President Donald Trump signed an order Monday freezing federal hiring.

The move follows up on a campaign promise he made to stop new hires for federal agencies, except jobs critical to health and safety. As part of Trump's 100-day action plan, the president said he would institute a hiring freeze on all federal positions "to reduce the federal workforce through attrition."

The executive order excludes the military and national security employees.

Alabama has more than 50,000 federal employees, 25,300 of whom are with the Department of Defense, mostly working at Redstone Arsenal in North Alabama.

The freeze has drawn the ire of federal employee unions.

"A hiring freeze will inevitably lead to the federal government outsourcing work, which has been proven to be far more costly than federal employees doing the work," said AFGE National President J. David Cox Sr. "Hiring freezes also have a disproportionate impact on veterans and minorities, who make up much of the federal workforce."

"For every day there's a hiring freeze, understaffed VA hospitals go without the doctors and nurses they desperately need, retirees wait in longer lines to visit their Social Security offices, and communities that depend on federal jobs for their economic survival suffer," he said.

Last month, the White House announced civilian employees and U.S. military personnel would receive a 2.1 percent pay raise on Jan. 1.

Federal employees received no raises for years 2011 - 2013, the height of the recession. Raises restarted in 2014, but employees only received a 1 percent boost in 2014 and 2015.