On Saturday morning, President Donald Tump took out is mobile phone, opened Twitter and accused former president Barack Obama of wiretapping his calls in Trump Tower, fuelling the political turmoil in the White House. 

Trump's accusation — leveled without any evidence — was denied first by president Obama. "Neither President Obama nor any White House official ever ordered surveillance on any U.S. citizen," Kevin Lewis, spokesman for the former president, said in a brief statement.

On Saturday afternoon,  FBI Director James B. Comey asked the Justice Department to issue a statement refuting President Trump’s claim that President Barack Obama ordered a wiretap of Trump’s phones before the election, according to U.S. officials, but the department did not do so.

Comey made the request on Saturday because of his concern that the allegation was false and suggested the FBI had broken the law, according to the New York Times. Unnamed US officials confirmed Comey’s move to the Associated Press, NBC News and the Wall Street Journal.

The department is yet to respond and the FBI has refused to comment on the reports about Comey’s request.

On Sunday, former US National Intelligence Director James Clapper, who served under former President Barack Obama, also denied President Donald Trump's conversations were tapped or recorded during last year's election campaign.

"For the part of the national security apparatus that I oversaw as DNI, there was no such wiretap activity mounted against the president-elect at the time, as a candidate, or against his campaign," Clapper, who was DNI chief from 2010-2017, said in an interview with NBC's "Meet the Press."

Clapper said that if such recordings had been made, or such tapping performed, he "certainly" would have known about it, adding that he could deny the existence of any judicial order permitting the FBI to monitor communications at Trump Tower in New York, the magnate's campaign headquarters, as reported in EFE.

In his claims early Saturday morning, the president tweeted that he “just found out” that Obama had “my 'wires tapped' in Trump Tower” before the election. Trump compared the alleged action to “McCarthyism.”

“Is it legal for a sitting President to be ‘wire tapping’ a race for president prior to an election?” Trump asked in another tweet. “Turned down by court earlier. A NEW LOW!”

By Sunday morning, the White House doubled down on Trump’s explosive tweet storm and asked  Congress to investigate whether Obama abused executive powers by allegedly ordering wiretaps during the 2016 presidential campaign.

"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," Sean Spicer, chief press officer at the White House, said in a statement.

 "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!" Trump tweeted in another of his early morning Saturday tweets.

Comey’s request is sure to raise eyebrows in light of his actions last year in the bureau’s investigation into Hillary Clinton’s email server, reported The Washington Post.

11 days before the election, Comey wrote Congress that the FBI was examining new emails that had come to light. Democrats say the move influenced the outcome of the election.

It is highly unusual for the director of the nation’s intelligence service to challenge a sitting president in this way and – since attorney general Jeff Sessions recused himself from the Russia investigation last week – Comey has reportedly struggled to find an authority able to respond to his request to the White House, reported The Guardian.

Also, i is not clear why Comey, who is the senior-most law enforcement officer who has been overseeing the FBI investigation from its inception in the Obama administration, did not himself issue a statement to refute Trump’s claims, as reported in The Washington Post.

According to The Economist, there are three explanations for Mr Trump’s accusation that Barack Obama ordered his phones to be tapped. None of them is comforting

The first is that Mr Trump’s stated suspicions are well-founded, and Mr Obama and his administration did, in fact, illegally spy on the nominee of one of the two main political parties.

The second explanation is that the FBI or other federal investigators legally spied on Trump Tower, the Trump campaign or figures close to the president. 

A third explanation for Mr Trump’s outburst is that he was trying to rally his supporters and discomfort his opponents "after a bumpy few days, once again involving furtive contacts between Team Trump and Russians. (now involving Trump's attorney-general and ideological mentor, Jeff Sessions).