President Donald Trump's allegation on Twitter that former President Barack Obama ordered wiretaps of his phones during the election caught senior federal law enforcement officials completely off-guard, sources close to the matter have told Fox News.

Those sources said that the officials in question had no idea what Trump was talking about when the president made the allegation on social media Saturday morning. The sources also told Fox that Trump did not consult with senior officials who would have been advised of any such wiretapping operations before posting the messages.

Trump claimed in a series of tweets without evidence Saturday that his predecessor had tried to undermine him by tapping the telephones at Trump Tower, the New York skyscraper where Trump based his campaign and transition operations, and maintains a home.



"How low has President Obama gone to tapp [sic] my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!" he tweeted.

Trump's charge also left many in the White House and Justice Department confused and scrambling over the weekend to find any kind of factual backup for the president's accusations.

Also Sunday, the New York Times reported that FBI Director James Comey asked the Justice Department to publicly reject Trump's assertion. According to the Times, Comey argued that Trump's claim falsely implied that the FBI had broken the law. The Justice Department had not issued any such statement as of Sunday evening.

Earlier Sunday, Obama's director of national intelligence, James Clapper, told NBC's "Meet the Press" that nothing matching Trump's claims had taken place.

"Absolutely, I can deny it," said Clapper, who also said that he had “no knowledge” of a request for a FISA, or Foreign Intelligence Surveillance Court Act, order for a wiretap, which requires at least some evidence of illegal activity.

White House press secretary Sean Spicer said without elaborating Sunday that Trump's instruction to Congress was based on "very troubling" reports "concerning potentially politically motivated investigations immediately ahead of the 2016 election." Spicer did not respond to inquiries about the reports he cited in announcing the request.

Spicer said the White House wants the congressional committees to "exercise their oversight authority to determine whether executive branch investigative powers were abused in 2016." He said there would be no further comment until the investigations are completed, a statement that House Minority Leader Nancy Pelosi, D-Calif., took offense to and likened to autocratic behavior.

"It's called a wrap-up smear. You make up something. Then you have the press write about it. And then you say, everybody is writing about this charge. It's a tool of an authoritarian," Pelosi said.

Spicer's chief deputy, Sarah Huckabee Sanders, said she thinks Trump is "going off of information that he's seen that has led him to believe that this is a very real potential."

Josh Earnest, who was Obama's press secretary, said presidents do not have authority to unilaterally order the wiretapping of American citizens, as Trump has alleged was done to him. FBI investigators and Justice Department officials must seek a federal judge's approval for such a step.

Earnest accused Trump of leveling the allegations to distract from the attention being given to campaign-season contacts by Trump aides with a Russian official, including campaign adviser Jeff Sessions before he resigned from the Senate to become attorney general. The FBI is investigating those contacts, as is Congress.

Senate Intelligence Committee Chairman Richard Burr, R-N.C., said in a statement that the panel "will follow the evidence where it leads, and we will continue to be guided by the intelligence and facts as we compile our findings."

Rep. Devin Nunes, R-Calif., chairman of the House Intelligence Committee, said in a statement that the committee "will make inquiries into whether the government was conducting surveillance activities on any political party's campaign officials or surrogates."

The committee's top Democrat, Rep. Adam Schiff of California, said Trump was following "a deeply disturbing pattern of distraction, distortion and downright fabrication."

The office of House Speaker Paul Ryan, R-Wis., referred questions to Nunes, while a spokesman for Senate Majority Leader Mitch McConnell, R-Ky., said McConnell would not tell the Senate committee how to do its work.

Trump said in the tweets that he had "just found out" about being wiretapped, though it was unclear whether he was referring to having found out through a briefing, a conversation or a media report. The president in the past has tweeted about unsubstantiated and provocative reports he reads on blogs or conservative websites.

Obama spokesman Kevin Lewis said Saturday that a "cardinal rule" of the Obama administration was not to interfere in Justice Department investigations, which are supposed to be conducted free of outside or political influence.

Lewis said neither Obama nor any White House official had ever ordered surveillance on any U.S. citizen. "Any suggestion otherwise is simply false," Lewis said.

Trump used a similar approach with his unsupported claims of massive voter fraud that he said caused him to lose the popular vote to Democrat Hillary Clinton. He eventually said he wanted to launch a "major" investigation to find the 3 million to 5 million votes he claims were cast illegally. Congressional leaders were cool to the idea — a costly and time-consuming effort.

Trump has been trailed for months by questions about his campaign's ties to Russia. Compounding the situation is the U.S. intelligence agencies' assessment that Russia interfered with the election to help Trump triumph over Hillary Clinton, along with disclosures about his aides' contacts with a Russian official.

Fox News' Matt Dean and Serafin Gomez contributed to this report. The Associated Press also contributed to this report.