The Social Security Administration, now under the control of an official installed by U.S. President Donald Trump, began the process of gutting whole segments of the agency and firing a huge portion of its already diminished workforce, sparking alarm among advocates who say the move will almost certainly result in benefit delays and disruptions.

The American Prospect, which first reported earlier this week that Acting SSA Commissioner Leland Dudek was weighing staff cuts of up to 50%, obtained an email sent late Thursday indicating that the department has launched an “agency-wide organizational restructuring that will include significant workforce reductions.”