Amid high-level turnover at the United States Department of Veterans Affairs, Trump administration critics are expressing alarm over whether politics is playing a role in the recent wave of removals, reassignments and retirements.

The department is currently run by Acting Secretary Peter O’Rourke and has been without a Senate-confirmed leader for months. Robert Wilkie, a former acting secretary who also served as the under secretary of defense for personnel and readiness, has been nominated for the top job by President Trump. If confirmed, Mr. Wilkie would take over the second-largest department in the federal government, overseeing a 360,000-person work force.

But he would be without several longtime employees who have recently left the department. The Washington Post reported on Wednesday that several unnamed current and former employees had raised alarms over what appeared to be a purge or reassignment of more than a dozen officials who were not loyal to the Trump administration.

“It’s been 112 days since the V.A. had a Senate-confirmed secretary in place, and many talented people have departed leadership positions within the V.A. over the past four months,” Joe Plenzler, a spokesman for the American Legion, a veterans service organization, said in an email on Wednesday.