The administration announced sweeping changes to the leadership of one of its largest cabinet departments on Monday, a day after the resignation of its longtime secretary signaled deeper turbulence inside the agency.

According to people briefed on the deliberations, several senior officials are expected to leave in the coming weeks, part of an effort to consolidate control over a department that has been the focus of intense political scrutiny.

Lawmakers from both parties expressed concern that the rapid turnover at the top would create a leadership vacuum at a moment when the agency is grappling with complex operational challenges.

Officials inside the department, speaking on condition of anonymity, said morale had suffered in recent months and that many career civil servants were uncertain about the direction of policy.