WASHINGTON — Attorney General William P. Barr said in an interview broadcast on Thursday that the special counsel, Robert S. Mueller III, should have decided whether his findings about President Trump’s efforts to impede the Russia investigation amounted to criminal activity.

“I personally felt he could have made a decision,” Mr. Barr told CBS News during an interview in Alaska, where he is visiting law enforcement officials. “But he had his reasons for not doing it, which he explained. And I’m not going to, you know, argue about those reasons.”

Mr. Barr reiterated his criticism of Mr. Mueller for his decision not to definitively conclude whether the president obstructed justice in his report that detailed 11 instances in which Mr. Trump tried to derail the special counsel’s work.

During a Senate hearing this spring, Mr. Barr also said that if Mr. Mueller was not going to “go down the path of making a traditional prosecutive decision, then he shouldn’t have investigated.”