WASHINGTON — Attorney General William Barr has given extra protection to the prosecutor he appointed to investigate the origins of the Trump-Russia probe, granting him authority to complete the work without being easily fired.

Barr told The Associated Press on Tuesday that he had appointed U.S. Attorney John Durham as a special counsel in October under the same federal regulations that governed special counsel Robert Mueller in the original Russia probe. He said Durham’s investigation has been narrowing to focus more on the conduct of FBI agents who worked on the Russia investigation.

Under the regulations, a special counsel can be fired only by the attorney general and for specific reasons.