"He's very, very good friends with Comey, which is very bothersome," Trump said. He added: "The people that have been hired are all Hillary Clinton supporters. Some of them worked for Hillary Clinton. I mean the whole thing is ridiculous, if you want to know the truth, from that standpoint."
Trump has talked privately with advisers and friends about the possibility of firing Mueller, something the president would have to do by ordering his Justice Department to remove him. But in the Fox interview, he seemed to want to give Mueller more time to continue the investigation before jumping to a conclusion.
"Robert Mueller is an honorable man, and hopefully he'll come up with an honorable solution," Trump said of the decorated former FBI director, criminal prosecutor and Marine.
With Mueller investigating Russia's meddling in the 2016 presidential election and its potential collusion with the Trump campaign — as well as possible obstruction of justice by Trump himself — the president maintained his innocence.
"Look, there has been no obstruction," Trump told Fox. "There has been no collusion. There has been leaking by Comey. But that's been no collusion, no obstruction — and virtually everybody agrees to that."
The interview was conducted by Ainsley Earhardt, a favorite of the Trump White House and co-host of "Fox & Friends," the cable network's reliably favorable morning show that the president often cheers on Twitter. She interviewed Trump and his wife, Melania, at the White House during Thursday night's congressional picnic.
Trump expressed optimism that the Senate would pass the Republican health-care bill revealed Thursday, saying the four GOP senators who stated their opposition were "friends" of his and would "probably get there."
"We have four very good people that — it's not that they're opposed; they'd like to get certain changes," Trump said. "And we'll see if we can take care of that." He added that health care is "a very complicated situation from the standpoint, you do something that's good for one group but bad for another."
Earhardt asked Trump about his announcement earlier Thursday that he had no "tapes" of his private conversations with Comey, coming clean after five-and-a-half weeks of speculating publicly that he may have been recording their talks. Trump suggested that his threat of tapes may have intimidated Comey into being more honest in his recollection of events.
"I didn't tape," Trump said. "And I don't have any tape, and I didn't tape. But when he found out that I, you know, that there may be tapes out there, whether it's government tapes or anything else, and who knows, I think his story may have changed. I mean, you'll have to take a look at that, because then he has to tell what actually took place at the events."
Trump continued: "My story didn't change. My story was always a straight story. My story was always the truth. But you'll have to determine for yourself whether or not his story changed."