Former Director of National Intelligence James Clapper says he was unaware of any FISA court order imposing surveillance on President Trump during the campaign or the transition period. Above, Clapper testified before the Senate Intelligence Committee, Jan. 10, 2017. Joshua Roberts/Reuters

UPDATE: 2:25 p.m. EST — House intelligence committee Chairman Devin Nunes said Sunday House Permanent Select Committee on Intelligence would examine whether “any political party’s campaign officials or surrogates” were the subject of government surveillance.

“And we will continue to investigate this issue of the evidence warrants it,” Nunes said in a statement.

Original story

Former Director of National Intelligence James Clapper denied Sunday there had been any order to wiretap Donald Trump during the 2016 election campaign or the transition.

But a White House spokeswoman said if any wiretapping did occur, it is the biggest abuse of power in U.S. history.

President Trump tweeted Saturday he had “just learned” his “wires” had been tapped in Trump Tower.

It was unclear on what Trump was basing his allegation, which came after Attorney General Jeff Sessions said he would recuse himself from the investigation of Russian hacking during the election and whether there were any ties between the Trump campaign and the Russian government.

Clapper, in an interview on NBC’s “Meet the Press,” said if there had been an order under the Foreign Intelligence Surveillance Act, he would have been aware of it.

“I will say that, 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, or some [other] candidate, or against his campaign. I can't speak for other Title Three authorized entities in the government or a state or local entity,” Clapper said.

Clapper said the investigation conducted by the National Security Agency, the FBI and CIA did not turn up “collusion between members of the Trump campaign and the Russians. There was no evidence of that included in our report.”

Clapper said, however, it is in “the current president’s interests, in the Democrats’ interests, in the Republican interest, in the country’s interest to get to the bottom of all this.”

Sens. Marco Rubio, R-Fla., on CNN’s “State of the Union” and "Meet the Press," Susan Collins, R-Maine, on CBS’ “Face the Nation,” and Chuck Schumer, D-N.Y., on “Meet the Press,” all called for full investigations, with Schumer pushing for a special prosecutor, of not only the president’s allegations but also of Russian efforts to influence the election.

“I've never heard that allegation made before by anybody. I've never seen anything about that anywhere before. But again, the president put that out there, and now the White House will have to answer as to exactly what he was referring to,” Rubio said on "Meet the Press."

In a statement from the White House early Sunday, press secretary Sean Spicer called the allegations of wiretaps “very troubling.”

“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. Neither the White House nor the president will comment further until such oversight is conducted,” the statement said.

White House spokeswoman Sarah Huckabee Sanders also called for an investigation of whether President Barack Obama ordered surveillance of Trump on ABC’s “This Week.”

“All we’re saying is let’s take a closer look. Let’s look into this. If this happened, if this is accurate, this is the biggest overreach and the biggest scandal,” Huckabee Sanders said.

“Look, I think he's going off of information that he's seen that has led him to believe that this is a very real potential. I think he’s made very clear what he believes, and he’s asking that we get down to the bottom of this, get the truth here.”

Huckabee Sanders said not only did reports of such surveillance show up in conservative media but in the New York Times and BBC as well.

“If they’re going to investigate Russia ties, let’s include this as part of it.

Former Attorney General Michael Mukasey told “This Week” Trump may not be “correct” but he could be “right.” He said the Justice Department could have sought surveillance through the FISA court if it was investigating whether anyone in the Trump organization was acting as a “foreign agent” working with or for the Russians during the investigation by intelligence agencies into the Russians’ hacking the email of the Democratic National Committee and Clinton campaign chairman John Podesta.