President Trump maintained Thursday that the Russia investigation had turned into a "witch hunt" against him, but refrained from directly criticizing the man at its helm or the appointment of a special counsel.

Deputy Attorney General Rod Rosenstein tapped former FBI Director Robert Mueller to oversee the investigation into Russian interference in the 2016 presidential election, including the question of whether Trump's campaign colluded with Moscow.

"I respect the move, but the entire thing has been a witch hunt," Trump said Thursday during a joint appearance with Colombian President Juan Manual Santos.

"And there is no collusion between certainly myself and my campaign, but I can always speak for myself — and the Russians, zero," Trump added.

Trump also said the focus on Russia "divides the country."

The appointment of a special counsel comes with big risks for Trump and takes the investigation out of his chain of command. But it also benefits the president by undermining calls for impeachment or an independent congressional committee while allowing the White House to defer all future Russia questions to Mueller's office — if Trump can maintain that level of message discipline.

Not long after Mueller's appointment, the tension between letting the special counsel take pressure off the White House and Trump's own desire to fight back was on display.

Trump's first comments after Mueller's Wednesday evening appointment showed restraint and a desire to move on from the Russia controversy, which threatened all week to upend his young presidency.

"As I have stated many times, a thorough investigation will confirm what we already know – there was no collusion between my campaign and any foreign entity," the president said in a statement issued by the White House.

"I look forward to this matter concluding quickly. In the meantime, I will never stop fighting for the people and the issues that matter most to the future of our country."

But on Thursday morning, Trump once again blew up the White House's carefully crafted talking points by trash-talking on Twitter. "This is the single greatest witch hunt of a politician in American history," he tweeted.

Trump also complained that his Democratic rivals didn't face special counsel-led investigations.

At his press conference later in the day, Trump remained defiant about an investigation he argued had become divisive and a distraction. But he also tried turn attention to his administration's agenda.

"[W]e've had tremendous success," Trump contended.

"You look at our job numbers, you look at what's going on at the border, as we discussed before; if you look at what will be happening — you're going to see some incredible numbers with respect to the success of General Mattis and others with the ISIS situation.

"The numbers are staggering, how successful they've been, the military has been."

The president said the focus should be on delivering for the American people.

"So I hate to see anything that divides," Trump said on Thursday. "I'm fine with whatever people want to do, but we have to get back to running this country really, really well."

In the 1990s, President Clinton regularly argued that the investigations dogging him were hurting his ability to run the country effectively.

"Anything that's a distraction, I dislike," Clinton said after Whitewater independent counsel Kenneth Starr won approval to expand his probe into the issues that ultimately led to his impeachment.

"These allegations are false. And I need to go back to work for the American people. Thank you," Clinton said of accusations he had sex with White House intern Monica Lewinsky.

"I am honored to work with this great president on his agenda to the nation, and I believe that it's time to put this matter behind us — once and for all — and move forward with the business of the United States of America," Vice President Al Gore said on the day Clinton admitted his Lewinsky denials were a lie.

Like Trump is attempting to do now, the Democrats exhorted the public to move on from the scandals. That's how the left-wing group MoveOn.org — which on Thursday repeated its call for Trump's impeachment in an email to supporters and over the weekend circulated a message from former Clinton Labor Secretary Robert Reich saying the president may be a "traitor"—got its name.

These tactics may have worked better for Clinton because he was more popular than Trump. During his second term, when the Lewinsky affair broke, Clinton's average approval rating stood at 61 percent, according to Gallup. Trump's approval rating is 39.7 percent, according to the latest RealClearPolitics polling average.

Clinton was personally critical of Starr, even after leaving office.

"No other President ever had to endure someone like Ken Starr indicting innocent people because they wouldn't lie, in a systematic way," Clinton said in 2004. "No one ever had to try to save people from ethnic cleansing in the Balkans and the people in Haiti from a military dictator who was murdering them and all the other problems I dealt with, while every day, an entire apparatus was devoted to destroying him."

Clinton wagged his finger at longtime ABC News anchor Peter Jennings, accusing him of cooperating with Starr. "The way your people repeated every little sleazy thing he leaked," the former president hissed. "No one has any idea what that's like."

Counterattacking has usually been Trump's approach too. On the campaign trail, he invoked the Mexican heritage of the judge who heard a lawsuit against Trump University and, earlier in his administration, he lashed out at the "so-called judge" who temporarily blocked his first attempt to pause the immigration flow from select Middle Eastern countries.

So far, Trump has not gone there with Mueller. But he is outraged his administration and election remains under a microscope.

"I think it's totally ridiculous. Everybody thinks so," Trump said Thursday when asked whether investigators could find him guilty of any illegal activity. He admitted he was surprised by the backlash against his abrupt firing of former FBI Director James Comey.

"I actually thought when I made that decision — and I also got a very, very strong recommendation, as you know, from the Deputy Attorney General, Rod Rosenstein," he said. "But when I made that decision, I actually thought that it would be a bipartisan decision, because you look at all of the people on the Democratic side — not only the Republican side — they were saying such terrible things about Director Comey."

Trump insisted there was one thing everyone could agree on.

"There was no collusion," he repeated. "And everybody — even my enemies have said, there is no collusion."