President Donald Trump on Thursday declared himself the target of a “witch hunt” a day after the Justice Department announced the appointment of a special counsel to investigate alleged Russian interference in the 2016 election.

"With all of the illegal acts that took place in the Clinton campaign & Obama Administration, there was never a special councel (sic) appointed!" he weighed in Thursday morning on Twitter, his favored form of communication.

"This is the single greatest witch hunt of a politician in American history!" he followed up.

With all of the illegal acts that took place in the Clinton campaign & Obama Administration, there was never a special councel appointed! — Donald J. Trump (@realDonaldTrump) May 18, 2017

This is the single greatest witch hunt of a politician in American history! — Donald J. Trump (@realDonaldTrump) May 18, 2017

At a White House lunch with anchors on Thursday, Trump was asked about the appointment of a special counsel.

"I believe it hurts our country terribly, because it shows we're a divided, mixed-up, not-unified country," the president said. "And we have very important things to be doing right now, whether it's trade deals, whether it's military, whether it's stopping nuclear...And I think this shows a very divided country.

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Trump added, "It also happens to be a pure excuse for the Democrats having lost an election that they should have easily won because of the Electoral College being slanted so much in their way. That's all this is. I think it shows division, and it shows that we're not together as a country. And I think it's a very, very negative thing. And hopefully, this can go quickly, because we have to show unity if we're going to do great things with respect to the rest of the world."

At a joint press conference later with Colombia President Juan Manuel Santos, Trump said he "respects" the naming of a special counsel but added, "I hate to see anything that divides" the country.

The president again insisted there was "zero" collusion with the Russians. "There is not collusion between, certainly myself and my campaign, but I can only speak for myself," Trump said. "Believe me, there's no collusion."

Trump also directly responded to reports that he asked then-FBI Director James Comey to stop the investigation into former National Security Adviser Mike Flynn, saying "no" twice when he was asked at the press conference if he tried to halt the probe. "Next question," the president said.

And Trump called talk of impeachment "ridiculous — everybody thinks so."

Some of Trump's comments Thursday about the special counsel stand in contrast to his more measured response Wednesday night from the president after Deputy U.S. Attorney General Rod Rosenstein appointed former FBI Director Bob Mueller to the investigatory role.

"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," Trump said in the statement. "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."

Related: Flynn, Manafort Are Key Figures in Russia Probe Mueller Will Lead

Mueller takes the reins after Comey was fired by Trump last week as he investigated potential ties between Trump's campaign and Russian officials.

Trump later revealed to NBC News that he thought of Comey as a "showboat" and "grandstander," and felt his inquiry was part of a "made-up story" — contradicting what his top aides had told reporters earlier in the week that the firing had nothing to do with Russia.

Related: Obstruction of Justice: What It Is and Why Trump Should Care

While Mueller begins his investigation, Congress has its own ongoing probe into Russia.

Washington lawmakers from both parties have expressed confidence in Mueller, a former federal prosecutor at the Justice Department who became FBI director just prior to 9/11.

"I think he'll be broadly supported, he has impeccable credentials, a storied history," Rep. Jason Chaffetz, R-Utah, and the chairman of the House Oversight Committee, said Thursday on TODAY. "He had 10 years leading the FBI in both the Bush and the Obama administration. ... He's in the latter part of his career, he has nothing to prove, I think he'll do a fabulous job."