WASHINGTON — Taking unprecedented action, a federal watchdog agency recommended Thursday that President Donald Trump fire one of his most ardent defenders, counselor Kellyanne Conway, for repeatedly violating a law that limits political activity by government workers.

The U.S. Office of Special Counsel, which is unrelated to Robert Mueller’s probe, said in a letter to Trump that Conway has been a “repeat offender” of the Hatch Act by disparaging Democratic presidential candidates while speaking in her official capacity during television interviews and on social media.

Federal law prohibits employees of the executive branch from using their official authority or influence to affect the result of an election. Trump and Vice President Mike Pence are exempt from the Hatch Act, but there are no exceptions for White House employees.

The agency does not have the authority to fire Conway, who was appointed by Trump, so it would be up to the president to follow its recommendation. Conway is known for her television appearances in support of the president and his policies. She helped him win election in 2016 as his campaign manager.

The recommendation to fire Conway is the first time the watchdog office has recommended the removal of a White House official over Hatch Act violations.