In an interview with the Fox News host Sean Hannity, President Donald Trump denounced the FBI officials who launched the Russia investigation taken over by the special counsel Robert Mueller.

"That was a disgrace and an embarrassment our country, that they were allowed to get away with this," Trump said. "Hopefully, they won't get away with it."

The president described the investigation as an attempt at "subversion" and "treason."

On Sunday, Attorney General William Barr said Mueller's investigation found no evidence that Trump's campaign illegally conspired with Russia.

President Donald Trump, in his first lengthy one-on-one interview since the special counsel Robert Mueller submitted his report on Russian election interference, denounced those who initiated the investigation, saying, "Hopefully, they won't get away with it."

Speaking with the Fox News host Sean Hannity, a friend who advocates Trump's positions on the air, the president renewed his attacks on intelligence officials, Democrats, and what he called FBI "dirty cops" whom he has long accused of running a "witch hunt" against his administration.

After criticizing the amount spent on the investigation, Trump said: "How did it start? You had dirty cops. You had people that are about FBI folks."

He remarked that "at the top, they were not clean, to put it mildly," adding, "And what they did to our country was a terrible, terrible thing."

The president went on to express his hope there would be payback for FBI officials who in 2016 began investigating contact between Russians and Trump campaign officials, an investigation that was handed over to Mueller in 2017 after Trump fired FBI Director James Comey.

The investigation examined Russian election interference in 2016 and sought to learn whether anyone associated with Trump's campaign illegally aided Russia in its efforts. It also examined whether Trump obstructed justice in connection to the investigation.

"I mean, you can never allow this to happen to another president," Trump said. "This can never, ever happen to a president again, Sean.

"That was a disgrace and an embarrassment our country, that they were allowed to get away with this. Hopefully, they won't get away with it."

Trump and his allies have been emboldened since Attorney General William Barr on Sunday told Congress that Mueller found no evidence that the Trump campaign illegally conspired with Russia. Earlier this week, Trump's 2020 campaign urged news networks to stop interviewing people who had used the Mueller investigation to attack Trump.

In Wednesday's interview, Trump accused FBI officials involved in the investigation of "treason," reiterating attacks on Peter Strzok and Lisa Page, two FBI officials who were found to have exchanged messages disparaging Trump.

"They wanted to do a subversion," he said. "It was treason. It was really treason."

He went on to attack other critics he said had accused him of collusion — including Rep. Adam Schiff, the Democratic House Intelligence Committee chairman, and the former CIA Director John Brennan, whom he described as a "sick person."

The president said he would leave it "to other people, including the attorney general, and others, to make a determination" about what should be done. "If someone tries the same thing," he said, "they have to know that the penalty will be very, very great, if and when they get caught.”

Mueller's report has yet to be made public. In a summary submitted to Congress on Sunday, Barr wrote that Mueller had not established that Trump's campaign illegally conspired with Russia to win the 2016 presidential election.

He also said, however, that Mueller declined to take a position on whether Trump obstructed justice, leaving it up to top Justice Department officials to determine that based on evidence uncovered in the investigation. Barr quoted Mueller as writing that "while this report does not conclude the President committed a crime, it also does not exonerate him." Barr ultimately concluded that Trump did not obstruct justice.

The investigation resulted in guilty pleas from several Trump officials, though none related to collusion with Russia, and charges filed against Russians accused of involvement in hacking and disinformation campaigns.