The largest union for government employees sued the Trump administration to block an executive order that strips federal workers of job protections.

The largest union representing U.S. government employees filed a lawsuit on Wednesday to block President Donald Trump's plan to reclassify up to 50,000 federal workers and make it easier to fire them.

Changeover among federal government agencies is normal when a new administration comes to Washington, with presidents regularly dismissing appointees selected by predecessors from opposing political parties.

Employees have until Feb. 6 to decide whether to take the buyouts offered by OPM or return to the office— in most cases, five days a week.