Did Obama really wiretap Trump Tower?

They were arguably Donald Trump's most striking claims to date: a series of tweets, accusing then. President Barack Obama of wire-tapping Trump Tower during the election.
The claim appeared to come as a surprise, and was not backed up by any evidence.
First Mr Obama's spokesman, then the former US intelligence chief James Clapper denied any wiretap had been ordered. But President Trump, via his press secretary Sean Spicer, has urged Congress to investigate the "troubling" claims, alongside its current investigations into allegations of Russian hacking during the election.
What does the FBI say?
FBI Director James Comey has reportedly denied the allegation and asked the US justice department to reject it.
He is said to have asked for the correction because it falsely insinuates that the FBI broke the law.
The New York Times and later by NBC quoted officials as saying that Mr Comey believed there was no evidence to support Mr Trump's allegation.
The justice department did not issue any immediate statement.
What are the Congressional committees already looking at?
Both the House and Senate intelligence committees are currently looking into the possibility of Russian interference during the 2016 election, inquiries 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".
Both committees have conceded these will be time-consuming investigations, and at least one member of the House intelligence committee has expressed his annoyance at another layer being added
"Ok @PressSec, as a member of the committee onto which you've dumped this mess, I look forward to seeing your evidence," Democrat Jim Himes tweeted.
Is there any evidence?
Mr Trump and his team have provided no evidence to say the phones at Trump Tower were wiretapped, and now Mr Clapper, who was then director of national intelligence, has categorically denied such an order existed.
As intelligence director, he told NBC, he would have known about a "Fisa court order on something like this".
This is a reference to the US Foreign Intelligence Surveillance Court, which can grant wiretaps on national security issues.

Could Obama have ordered the surveillance?
Mr Obama's team have outright denied any involvement, saying Mr Trump's tweets are "simply false".
A warrant, if it existed, would most likely have been ordered by the Department of Justice independently of the White House.
On Sunday, former press secretary Josh Earnest told ABC: "This may come as a surprise to the current occupant of the Oval Office, but the president of the United States does not have the authority to unilaterally order the wiretapping of an American citizen.
"If the FBI decided to use their wiretapping authority in the context of the counterintelligence or criminal investigation, it would require FBI investigators, officials at the Department of Justice going to a federal judge, and making a case, and demonstrating probable cause to use that authority to conduct the investigation. That is a fact."

What is the Fisa court?
The Fisa court has been described by CNN as possibly "the most powerful court you have never heard of".
The secretive court approves surveillance warrants under Fisa against "agents of a foreign power", mainly to either the FBI or NSA.
In this case, the reported target of the FBI's application was two Russian banks.
Any application has to be approved by one of 11 sitting judges.
Where did the wiretap claim come from?
Rumours of an order granted under the Foreign Intelligence Surveillance Act (Fisa) have been circulating for some time.
On 7 November - the day before the country went to the polls - former British MP Louise Mensch reported the order was approved in October..
According to Ms Mensch, it was issued in connection with a private server and activity between two Russia banks.