Photo: The Canadian Press

President Donald Trump boards Air Force One in Morristown, N.J., on Sunday.

Capping a week of drama, back-tracking and blistering statements from allies about his attitude toward Russian election interference, President Donald Trump on Monday returned to familiar rhetoric, referring to the special counsel's Russia probe as a "hoax" and "Witch Hunt."

Trump spent last week trying to reassure the country that he accepts that the longtime foe interfered in the 2016 election, despite his public undermining of U.S. intelligence agencies in Helsinki while standing alongside Russian President Vladimir Putin. But Trump cast doubt once again in a Sunday tweet, diminishing at least the significance, if not the existence, of the interference and the U.S. investigation into Russia's actions.

"So President Obama knew about Russia before the Election," Trump tweeted. "Why didn't he do something about it? Why didn't he tell our campaign? Because it is all a big hoax, that's why, and he thought Crooked Hillary was going to win!!!"

White House press secretary Sarah Sanders said Monday that Trump was "obviously" referring to allegations of collusion between his presidential campaign and Russian agents.

U.S. intelligence agencies unanimously concurred that Russia interfered in the 2016 campaign. Trump only reluctantly accepted their assessment amid the firestorm of last week's reaction to his comments at a summit news conference with Putin.

"Obviously the president is talking about the collusion with his campaign," Sanders said. "He's been very clear that there wasn't any. I think he's said it about 1,000 times."

On Monday, Trump claimed the FBI inappropriately used political research by British spy Christopher Steele to mislead the court into granting a wiretap order on onetime campaign adviser Carter Page, then classified the documents to "cover up misconduct." 

Released online Saturday under the Freedom of Information Act, the documents note the political ties to Steele's work but said it still believed some of his report to be "credible." The FBI said it suspected Page had been "collaborating and conspiring with the Russian government."

Visible portions of the heavily redacted documents, released Saturday under the Freedom of Information Act, show the FBI telling the court that Page "has been collaborating and conspiring with the Russian government." The agency also told the court that "the FBI believes Page has been the subject of targeted recruitment by the Russian government."

Page denies being a foreign agent.

Special Counsel Robert Mueller is investigating potential collusion between Russia and Trump's campaign. Two Trump associates, former national security adviser Mike Flynn and campaign foreign policy aide George Papadopoulos, pleaded guilty last year to charges brought by Mueller alleging they had lied to the FBI about their Russia contacts.

Trump tweeted Monday: "They should drop the discredited Mueller Witch Hunt now!"