WASHINGTON — More than 1,100 former federal prosecutors and Justice Department officials called on Attorney General William P. Barr on Sunday to step down after he intervened last week to lower the Justice Department’s sentencing recommendation for President Trump’s longtime friend Roger J. Stone Jr.

They also urged current government employees to report any signs of unethical behavior at the Justice Department to the agency’s inspector general and to Congress.

“Each of us strongly condemns President Trump’s and Attorney General Barr’s interference in the fair administration of justice,” the former Justice Department lawyers, who came from across the political spectrum, wrote in an open letter on Sunday. Those actions, they said, “require Mr. Barr to resign.”

The sharp denunciation of Mr. Barr underlined the extent of the fallout over the case of Mr. Stone, capping a week that strained the attorney general’s relationship with his rank and file, and with the president himself.