President Trump tweeted his objection to the appointment of a special counsel to investigate possible collusion between his associates and the Russian government during the 2016 presidential election. (Victoria Walker,Jayne Orenstein,Dalton Bennett,Jenny Starrs/The Washington Post)

President Trump described himself as the victim of a “witch hunt” Thursday morning, a day after the Justice Department appointed a special counsel to investigate possible collusion between  Trump associates and the Russian government to meddle in the 2016 presidential election.

In a pair of tweets Thursday shortly before 8 a.m., Trump — without evidence — pointed to “the illegal acts” he claimed occurred during Hillary Clinton's presidential campaign and President Barack Obama's administration, expressing anger that a special counsel had never been appointed to investigate his Democratic rivals.

He also misspelled “counsel” as “councel.”

“With all of the illegal acts that took place in the Clinton campaign & Obama Administration, there was never a special councel appointed!” Trump wrote. “This is the single greatest witch hunt of a politician in American history!”

Thursday was not the first time Trump has made baseless claims without providing any evidence. Trump helped launch his political career by claiming — incorrectly — that Obama was not born in the United States, and as president he asserted on Twitter, again with no evidence, that the Obama administration had wiretapped his campaign headquarters.

The Washington Post's Devlin Barrett explains the Justice Department's decision to appoint Robert Mueller as special counsel to investigate possible connections between the Trump campaign and Russian officials. (Peter Stevenson,Jason Aldag,Whitney Leaming/The Washington Post)

But Trump's missives on Twitter — where the president most frequently turns to express his sense of grievances — not only underscore that he disagrees with his own Justice Department, but undercut claims by his own aides Wednesday that he had processed the news with grace and calm.

One senior White House official who was present when Trump was informed of the Justice Department's decision to appoint as special counsel Robert S. Mueller III, a former prosecutor who served as the FBI director from 2001 to 2013, described Trump as “unbelievably calm and measured.”

“I expected him to be ranting and raving, but he was like, 'Fine, let them do what they have to do, but we'll be focused on our agenda,'" said the official, who requested anonymity to describe the private talks.

Rod J. Rosenstein, the deputy attorney general, said in a statement that he had appointed Mueller to investigate possible interference in the 2016 presidential election because he believed it was in “the public interest.”

And in a statement Wednesday evening, Trump offered a more measured outlook, saying, “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.”

“I look forward to this matter concluding quickly,” the president wrote.