The director of the Centers for Disease Control and Prevention is refusing to leave her post, despite demands from Health Secretary Robert F. Kennedy Jr. that she quit or be fired, according to her lawyers and an administration official familiar with the events.

The clash between Mr. Kennedy and Susan Monarez, who was sworn in as C.D.C. director just one month ago, burst into public view on Wednesday as four other high-ranking C.D.C. officials quit en masse, apparently in frustration over vaccine policy and Mr. Kennedy’s leadership.

Late Wednesday afternoon, the Department of Health and Human Services announced on X that Dr. Monarez was “no longer” director of the C.D.C.

Without elaborating, the agency thanked her for “her dedicated service to the American people,” adding, “@SecKennedy has full confidence in his team at @CDCgov who will continue to be vigilant in protecting Americans against infectious diseases at home and abroad.”

Hours later, Abbe David Lowell and Mark S. Zaid, high-profile lawyers, disputed the department’s account, saying Dr. Monarez “has neither resigned nor received notification from the White House that she has been fired, and as a person of integrity and devoted to science, she will not resign.”

Mr. Kennedy and his department, they said, “have set their sights on weaponizing public health for political gain and putting millions of American lives at risk.”