President Donald Trump on Saturday called it a “fact” that Obama had tapped Trump Tower phones. | Getty Lawmakers stunned, baffled by Trump’s wiretap allegations The White House, meanwhile, is pushing for a probe of the Obama administration. 
 
 Congressional Republicans were flummoxed Sunday by President Donald Trump's and his White House’s continued assertions — provided without evidence — that President Barack Obama had wiretapped Trump Tower during the 2016 presidential campaign. 
 
 A day after Trump made the charge, Hill Republicans were largely mute, and those who spoke out were perplexed at the source of Trump’s information, which the White House has yet to disclose. 
 
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 Sen. Marco Rubio said Sunday he had seen “no evidence” to back up Trump’s wiretap claims. Rubio is a member of the Senate Intelligence Committee, which is investigating Trump’s ties to Russia and has received classified briefings on the issue. 
 
 “I'd imagine the president and the White House in the days to come will outline further what was behind that accusation,” the Florida Republican said on NBC’s “Meet the Press.” “The president put that out there, and now the White House will have to answer as to exactly what he was referring to.” 
 
 Rubio’s comments came a day after Nebraska GOP Sen. Ben Sasse, a longtime Trump critic, said Trump owed it to the public to share more details about his allegation. Other Republican lawmakers who have clashed with Trump made similar demands for more information. 
 
 “It would be more helpful if he turned over to the intelligence committee any evidence that he has,” said Sen. Susan Collins (R-Maine), a member of the Senate Intelligence Committee, on CBS' "Face the Nation." 
 
 Trump suggested Saturday that “a good lawyer could make a great case out of the fact that President Obama was tapping my phones in October, just prior to Election!” In a separate tweet, he wrote “Just found out that Obama had my 'wires tapped' in Trump Tower just before the victory. Nothing found. This is McCarthyism!” 
 
 Trump’s allegations raised questions about whether federal authorities had obtained a legal warrant to tap Trump's or his associates’ calls, perhaps through the Foreign Intelligence Surveillance Court, which can authorize wiretaps against potential foreign spies. Those orders are typically classified, and Trump’s comments sent Washington scrambling to understand his allegations. 
 
 One lawmaker who did support his call for an investigation was Rep. Devin Nunes (R-Calif.), the head of the House intelligence panel. "The Committee will make inquiries into whether the government was conducting surveillance activities on any political party’s campaign officials or surrogates, and we will continue to investigate this issue if the evidence warrants it,” he said in a statement. 
 
 But otherwise, even some of Trump's strongest supporters were cautious about rushing to his defense. 
 
 On "Fox News Sunday," Sen. Tom Cotton (R-Ark.) said he had no evidence that what Trump said was true: "It doesn't mean that none of these things have happened, just means I haven't seen them yet." 
 
 Part of the confusion stems from the fact that, according to GOP sources, the White House gave no advance notice to congressional Republicans that Trump would be raising the issue of wiretaps this weekend, leaving both sides scrambling to figure out what Trump was referring to and how to respond publicly. 
 
 Meanwhile, congressional Democrats said Trump’s flailing at his predecessor is a sign that he’s feeling squeezed by the federal investigation into his associates’ ties to Russia. Senate Minority Leader Chuck Schumer of New York said Trump’s charge, if proved false, is proof he “doesn’t know how to conduct himself.” And if it’s true, “it’s even worse,” because it means federal authorities saw a legal basis to authorize a wiretap, which requires a judge’s signoff. 
 
 “Either way … the president is in trouble,” Schumer said on “Meet the Press.” 
 
 House Democratic leader Nancy Pelosi of California said on CNN’s “State of the Union” that Trump’s allegation about Obama was a classic diversion tactic. 
 
 “This is called a wrap-up smear,” she said. “You make up something, then you have the press write about it, then you say everybody is writing about this charge. It’s the tool of an authoritarian, to just have you always be talking about what you want them to be talking about it.” 
 
 Rep. Adam Schiff, the ranking Democrat on the House intelligence panel, was also highly critical: "For a president of the United States to make such an incendiary charge — and one that discredits our democracy in the eyes of the world — is as destructive as it was baseless." 
 
 Sen. Mark Warner, the top Democrat on the Senate intelligence panel, said Sunday that he’ll be visiting with intelligence officials this week for an “unprecedented” look at the intelligence behind allegations of Russian meddling in the 2016 election and potential connections to Trump associates. The Virginia lawmaker added that he had seen no evidence — despite Trump’s claims — that federal officials had authorized a wiretap of Trump Tower, Trump’s campaign headquarters. 
 
 “We are early into this investigation,” he said, praising Republican colleagues on the committee like Rubio, Collins and Missouri Sen. Roy Blunt for cooperating with Democrats on the probe. 
 
 Warner’s comments followed a similar assertion by former Director of National Intelligence James Clapper, who said “I can deny” that there was any request by the FBI for a warrant to tap phones in Trump Tower. 
 
 "It's in everyone's interest — the current president's interest, Democrats' interest, Republicans' interest, the country's interest — to get to the bottom of all this, because it's such a distraction. Certainly the Russians have to be chortling at the success of their efforts to sow dissension in this country," he said on NBC’s “Meet the Press.” 
 
 Clapper added that he continues to believe that Russia meddled in the election on Trump's behalf, as U.S. intelligence agencies concluded in a declassified January report, but that "no evidence of collusion" between Moscow and Trump aides has been discovered. 
 
 Trump aides were caught Sunday defending the president’s accusation about Obama without any evidence to back them up. And they sought to shift the focus to Congress, by calling on the House and Senate intelligence committees — already probing potential Trump ties to Russia — to include an investigation of any illegal wiretapping by the Obama administration. 
 
 “I think what is necessary is Congress doing its job. Let them investigate,” said deputy White House press secretary Sarah Huckabee Sanders in an interview on ABC’s “This Week.” 
 
 Sanders presented no evidence of any improper actions by the Obama administration, and she refused to repeat Trump’s explosive Saturday tweets accusing Obama of spying on him and his team. Pressed repeatedly by host Martha Raddatz, Sanders said Trump was merely wondering about illegal wiretapping — despite Trump declaring it as fact just a day earlier. 
 
 “I think he is going off of information that he’s seeing that has led him to believe this is a very real potential,” she said, adding, “He’s talking about: ‘Could this have happened?’” 
 
 Trump on Saturday said that Obama had tapped Trump Tower phones, despite no evidence of his predecessor’s involvement. His claim appeared to be based on right-wing media reports raising questions about whether Trump associates had been surveilled. On Sunday, the press secretary stated: "President Donald J. Trump is requesting that as part of their investigation into Russian activity, the congressional intelligence committees exercise their oversight authority to determine whether executive branch investigative powers were abused in 2016." 
 
 Obama White House spokesman Josh Earnest insisted Sunday that any wiretaps authorized against Trump or his associates arose only from legal law enforcement authority. 
 
 “The president of the United States does not have the authority to unilaterally order the wiretapping of an American citizen,” he said, noting that such taps are approved by judges based only on evidence in a criminal or counterintelligence investigation. 
 
 Earnest said the White House kept FBI investigations at arm’s length and didn’t attempt to “influence or dictate” how those probes were conducted. 
 
 The Trump administration’s call for Congress to investigate wiretaps targeting Trump or his associates comes as the House and Senate intelligence committees have already launched probes into whether top Trump allies had contacts with Russian officials during the 2016 campaign. Nunes has also emphasized that he intends to probe leaks of classified information that have made their way into media reports since the election. 
 
 The general consensus Sunday was that the controversy indicated that more light needs to be shined on Russian meddling in the election. 
 
 "It underscores the necessity, and indeed the inevitability, of an independent investigation," Tom Donilon, Obama's national security adviser from 2010 to 2013, told Fareed Zakaria on CNN's "Fareed Zakaria GPS." 
 
 Rebecca Morin contributed to this report. ||||| Media playback is unsupported on your device Media caption James Clapper says he "can deny" that Donald Trump's phones were tapped 
 
 The director of national intelligence at the time of the US election has denied there was any wire-tapping of Donald Trump or his campaign. 
 
 James Clapper also told NBC that he knew of no court order to allow monitoring of Trump Tower in New York. 
 
 Mr Trump had accused President Barack Obama of ordering the wire-tap but offered no evidence. 
 
 The White House has asked Congress to examine whether the Obama administration abused its powers. 
 
 Meanwhile, the New York Times quoted senior officials as saying that FBI director James Comey had asked the justice department to publicly dismiss Mr Trump's allegation this weekend. 
 
 The officials were quoted as saying that Mr Comey believed there was no evidence to support the allegation, which he thought insinuated the FBI had broken the law. 
 
 However, the justice department has made no such statement, and the Times said neither it nor the FBI had officially commented. 
 
 Read more 
 
 James Clapper, who left his post when Mr Trump took office on 20 January, told NBC's Meet the Press: "There was no such wire-tap activity mounted against the president-elect at the time, as a candidate, or against his campaign." 
 
 He said that as intelligence director he would have known about any "court order on something like this. Absolutely, I can deny it". 
 
 But he added: "I can't speak for other authorised entities in the government or a state or local entity." 
 
 Some media reports had suggested a warrant was sought from the foreign intelligence surveillance court (Fisa) in order to monitor members of the Trump team suspected of irregular contacts with Russian officials. 
 
 Image copyright Reuters Image caption Mr Trump's press secretary said the president would not comment further, despite calls for him to back up his claims with evidence 
 
 Mr Clapper's comments appear to contradict the reports, which said that a warrant was at first turned down, but then approved in October. 
 
 Under Fisa, wire-tapping can only be approved if there is probable cause to believe that the target of the surveillance is an agent of a foreign power. Mr Obama could not lawfully have ordered such a warrant. 
 
 'Simply false' 
 
 In his interview, Mr Clapper also said that no evidence had been found of collusion between the Trump team and the Russian government. 
 
 Mr Trump, who has faced intense scrutiny over alleged Russian interference in support of his presidential bid, made his wire-tapping allegation in tweets written from his weekend home in Florida early on Saturday. 
 
 He called the alleged tapping "Nixon/Watergate", referring to the notorious political scandal of 1972, which led to the downfall of President Richard Nixon. 
 
 His claims sparked Republican and Democrat politicians alike to demand details to back them up. Florida Republican Senator Marco Rubio was the latest, saying on Sunday that "the White House will have to answer as to exactly what he was referring to". 
 
 Blowing up the rule book: Analysis by Laura Bicker, BBC News, Washington 
 
 Let's face it, Donald Trump is not your run-of-the-mill president. He's unorthodox. It's what his supporters love about him and why they elected the political outsider. 
 
 But accusing your predecessor of an abuse of power without proof isn't just throwing out the presidential rule book, it's blowing it up. 
 
 The attack was strikingly personal and the charge was astonishing. 
 
 President Trump's assertions appear to be based, in part, on unproven reports by Breitbart News and conservative talk radio hosts. 
 
 But President Trump has full access to intelligence reports. He could just ask if his phones at Trump Tower had been tapped or the information could have come from a briefing. 
 
 In which case has he divulged a secret? And where is his evidence? 
 
 Congress will want to know before they add this allegation to their current investigation. 
 
 But in his series of tweets on Sunday, White House Press Secretary Sean Spicer did not provide any further evidence. 
 
 He said: "Reports concerning potentially politically motivated investigations immediately ahead of the 2016 election are very troubling. 
 
 "President Trump is requesting that as part of their investigation into Russian activity, the congressional intelligence committees exercise their oversight authority to determine whether executive branch investigative powers were abused in 2016." 
 
 He added: "Neither the White House nor the President will comment further until such oversight is conducted." 
 
 White House deputy press secretary Sarah Huckabee Sanders told ABC News that if Mr Trump's allegations were true, "this is the greatest overreach and the greatest abuse of power that I think we've ever seen and a huge attack on democracy itself". 
 
 Image copyright AP Image caption Adam Schiff said Mr Trump's allegation "discredits our democracy in the eyes of the world" 
 
 There was a mixed reaction to Mr Trump's calls for the inquiry into alleged abuse of executive power. 
 
 Arkansas Republican Senator Tom Cotton said: "I'm sure that this matter will be a part of that inquiry." 
 
 But Adam Schiff, the most senior Democratic member of the House Select Committee on Intelligence, said Mr Trump's wire-tapping claim had been taken from "little more than... conspiracy-based news". 
 
 He said: "For a president of the United States to make such an incendiary charge - and one that discredits our democracy in the eyes of the world - is as destructive as it was baseless." 
 
 What are the Congressional committees looking at? 
 
 Both the House and Senate intelligence committees are currently looking into the possibility of Russian interference during the 2016 election, both launched in January. 
 
 They have promised wide-ranging investigations, carried out on a bipartisan basis, which will not shy away from looking into potential links between the Trump campaign and the Kremlin, as well as Russian "cyber activity". 
 
 Meanwhile, the Senate Armed Services Committee is going to look at how to protect the US from cyber-attacks in the wake of the election. 
 
 Mr Trump's tweets followed allegations made by conservative radio host Mark Levin and later carried in Breitbart News, of which Mr Trump's chief strategist Steve Bannon is a former executive chairman. 
 
 Mr Obama's spokesman, Kevin Lewis, called the accusations "simply false". 
 
 A "cardinal rule of the Obama Administration was that no White House official ever interfered with any independent investigation led by the Department of Justice", he said. ||||| House Intelligence Committee Chairman Devin Nunes (R-Calif.) on Wednesday said that his panel has not received any evidence that President Trump was wiretapped during the election campaign. 
 
 "As I told you last week about the issue with the president talking about tapping Trump Tower, that evidence still remains the same, that we don't have any evidence that that took place," Nunes told reporters. 
 
 "In fact, I don't believe just in the last week of time, the people we've talked to, I don't think there was an actual tap of Trump Tower." 
 
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 It is not the first time Nunes has stated that there is no evidence to suggest Trump was wiretapped. 
 
 In a series of tweets earlier this month, Trump leveled the explosive allegation that former President Obama had ordered surveillance of Trump's phone lines. Trump provided no evidence for his claim. 
 
 FBI Director James Comey urged the Justice Department to denounce Trump's statement because of a lack of evidence, but the agency has not done so. The Justice Department was expected to turn over to the House Intelligence Committee any information backing up Trump's claim by Monday. 
 
 White House press secretary Sean Spicer on Tuesday said Trump is "extremely confident" that the Justice Department will produce evidence to back up his assertion. He said Trump believes the evidence will “vindicate him.” 
 
 “I think there’s significant reporting about surveillance techniques that existed throughout the 2016 election,” Spicer said.
– FBI Director James Comey has waded into the controversy surrounding President Trump's claim that he was wiretapped by former President Obama last fall, the New York Times reports. Officials say Comey has asked the Justice Department to publicly reject Trump's explosive claim, both because he believes it's false and because he believes it suggests the FBI was engaged in illegal behavior. The Times' sources say senior FBI officials are also worried that if the public believes there was a court-approved Trump wiretap, they might expect them to find solid evidence of Russian interference in last year's election. In other coverage: The White House has demanded a congressional investigation of its claims, though lawmakers from both parties say they want more evidence to back up Trump's allegations, NBC News reports. "I've never heard that allegation made before by anybody," GOP Sen. Marco Rubio said Sunday. Key members of Congress say they will obey Trump's request, though the AP notes that any such investigation could be risky for Trump, since Democrats will have access to evidence, including any findings that could be damaging to the president. We "will follow the evidence where it leads, and we will continue to be guided by the intelligence and facts as we compile our findings," Sen. Richard Burr, the Republican chair of the Senate Intelligence Committee, said Sunday. Politico has more on the "baffled" reaction of lawmakers to Trump's claims, with even some of the president's closest allies wary about discussing the allegations. The Washington Post says it interviewed 17 White House officials and others for a report on Trump's "fury" at leaks and other setbacks in the days surrounding his Obama accusation. The New York Times looks at how the accusation took around 36 hours to go from an "unfounded conspiratorial rant" on conservative talk radio to Trump's Twitter feed. Former Attorney General Michael Mukasey says he believes there may have been surveillance of Trump Tower, but he doesn't think Obama ordered it, the Hill reports. Mukasey, who served in the George W. Bush administration, told ABC's This Week that the Justice Department could have ordered a wiretap in the belief "that somebody in Trump Tower may have been acting as an agent of the Russians for whatever purpose."