The website for the U.S. Agency for International Development went dark Saturday afternoon as lawmakers and aid workers, already reeling over the recent freezes to foreign assistance and the suspension of senior officials, braced for the possibility that the agency might be shut down.

A slimmed-down page for U.S.A.I.D. appeared on the State Department’s website Saturday afternoon, suggesting that the agency’s activities — which are currently severely limited — had been brought under the State Department’s umbrella.

Democratic lawmakers and aid workers have been gripped since Friday by reports that President Trump was planning to issue an executive order dismantling the aid agency and moving its work to the State Department.

Mr. Trump has made no secret of his disdain for the scope of American foreign aid, arguing that sending taxpayer dollars overseas runs counter to his America first agenda.

By Saturday, lawmakers had received word that at least some of the U.S.A.I.D. signs at the agency’s headquarters in downtown Washington had come down, and rumors were circling that mission directors around the world were being called back to the United States. Those reports could not be independently verified.

Two U.S.A.I.D. employees, who work in the Washington headquarters and spoke on condition of anonymity because of an order barring employees from discussing any changes to the agency, said that they were working under an atmosphere of fear and chaos, and that half of the agency’s work force had been eliminated in the last week.