WASHINGTON — In a rambling, grievance-filled interview, President Trump on Thursday threatened to intervene in the Justice Department’s Russia investigation, again derided former FBI Director James B. Comey as “a leaker and … a liar,” and defended allies under investigation.

Trump also used the wide-ranging half-hour phone conversation with the hosts of “Fox & Friends” to praise his handling of Iran and North Korea, and said his accomplishments as president were unparalleled.

“I would give myself an A-plus,” he said.

Yet even in that friendly territory, the focus came back again and again to what Trump called the “phony cloud” of controversy surrounding him.

He flared with anger at the Justice Department, which he said should be investigating his enemies instead of him.

“I’m very disappointed in my Justice Department,” he said.

The FBI’s actions in investigating his former campaign chairman, Paul Manafort, and his personal lawyer, Michael Cohen, were an “absolute disgrace,” Trump added, citing particularly the ways federal officials searched for evidence at their homes and offices.

“That’s not the FBI, that’s a fix,” he said.

He also suggested that his pledge not to intrude on the Russia investigation — a vow he has broken many times with verbal suggestions to Atty. Gen. Jeff Sessions — could be reversed.

“I have decided that I won’t be involved. I may change my mind at some point, because what’s going on is a disgrace,” he said.

The president also perhaps stoked concerns among some members of Congress from both parties that he might try to fire the two men in charge of the Russia inquiry, Deputy Atty. Gen. Rod Rosenstein and special counsel Robert S. Mueller III.

He referred caustically to the “witch hunt with people in the Justice Department who shouldn’t be there.”

Trump indicated that he had watched some of CNN’s Wednesday night town hall discussion with Comey, whom the president fired last spring and who has resurrected his criticisms of Trump on a book tour for his new memoir.

“I did a great thing for the American people by firing him,” Trump said. “Look, Comey is a leaker and he’s a liar and not only on this stuff — he’s been leaking for years.”

Trump insisted that memos Comey had given a friend recounting conversations with Trump were not only false but classified, a charge the former FBI director has denied.

“He is guilty of crimes, and if we had a Justice Department that was doing their job,” Trump said before being interrupted by the Fox News hosts, who repeatedly struggled to keep the president on topic.

On policy, Trump once again criticized the Iran nuclear deal; he faces a May 12 deadline to decide whether to pull out of the agreement.

The topic was prominent in Trump’s talks earlier this week with French President Emmanuel Macron, who pleaded with Trump to remain part of the multinational 2015 agreement.

“He came to recognize, I can say it from my standpoint, he is viewing, I believe, Iran a lot different than he did before he walked into the Oval Office,” Trump said of Macron.

However, in Macron’s address to a joint session of Congress on Wednesday, he outlined additions to the deal to placate Trump, but stood by the agreement and said the United States should too.

Trump called Iran “a real problem for this country,” but said that he had forced Iran into behaving better than it did under President Obama.

He also said he was looking forward to meeting with North Korean dictator Kim Jong Un. And he mocked people who, he said, expected him to engage in a nuclear war with a country whose leader he has often derided in the past.

“It was very, very nasty with ‘Little Rocket Man’ and with the buttons — ‘my button’s bigger,’” he said, recounting his tweeted gibes at Kim. “Everyone says, ‘This guy is going to get us into nuclear war.’ Let me tell you: Nuclear war would happen if you had weak people.”

He also continued to exaggerate Kim’s promises leading up to the proposed summit.

“I haven’t given up anything. I haven’t even talked about it,” he said. “They have given up denuclearization, testing, research, [said] ‘we’re going to close different sites.’ ... They gave it up before we even asked.”

While North Korea has paused some of its nuclear activities, it has not promised a permanent change, including giving up its nuclear weapons — and its vows in the past have proved to be fleeting.

The interview came just minutes after Trump’s nominee as secretary of Veterans Affairs, White House physician Rear Adm. Ronny Jackson, withdrew under a torrent of allegations about his personal conduct.

Trump called the accusations false.

“They’re trying to destroy a man,” he said, blaming Democrats.