WASHINGTON — Former Director of National Intelligence James R. Clapper said Sunday he would have known and that there were no wiretaps at Trump Tower or against Donald Trump or his campaign during his tenure.

Speaking on NBC’s Meet the Press, Clapper said “there was no such wiretap activity mounted against the president-elect at the time, as a candidate or against his campaign.”

Pressed on whether he would know whether the FBI had obtained a Foreign Intelligence Surveillance Court order to wiretap the Trump campaign, Clapper said he would have known and that none existed “to my knowledge,” and none was authorized for Trump Tower, the president’s campaign headquarters last year.

The statement followed President Trump’s claim, in a series of tweets early Saturday, that President Barack Obama “had my ‘wires tapped’ in Trump Tower just before the victory. Nothing found. This is McCarthyism!” and, minutes later, “Is it legal for a sitting President to be ‘wire tapping’ a race for president prior to an election? Turned down by court order. A NEW LOW!”

The Sunday news interview shows focused on the Trump wiretap allegation, the campaign’s alleged contacts with Russian officials and Attorney General Jeff Sessions’ decision last week to recuse himself from any investigation of the 2016 presidential race. The recusal came after press reports established that Sessions, a Trump campaign surrogate, testified under oath during his confirmation hearing that he had not met with Russian officials but had in fact met twice with Russian Ambassador Sergey Kislyak.

Sen. Marco Rubio of Florida, a sometime Trump critic who serves on the Intelligence Committee, said on Meet the Press regarding the wiretap claim that he had “never heard that allegation made before by anybody…But again, the president put that out there, and now the White House will have to answer to exactly what he was referring to.”

Sen. Marco Rubio (R-FL), Chairman of the Congressional Executive Commission on Human Rights speaks at a hearing on Capitol Hill March 1, 2017 in Washington, DC.

Former CIA and Defense Secretary Leon Panetta, on CBS’ Face the Nation, said that Trump is making the same mistake other presidents have during scandals by seeking to “divert attention, trying to obfuscate, trying to cover up,” but that truth will come out.

“This issue is not going away,” he said. “There’s too much here.”

“Every time he tweets, every time these issues come up that indicate that there’s obviously something to this Russia issue, and the administration is not cooperating when that happens, when he accuses a past president of wiretapping without any evidence of that being the case, it makes us vulnerable…It makes us vulnerable to our enemies,” Panetta said.

Maine Sen. Susan Collins, a Republican on the Intelligence Committee looking into the Russian influence in last year’s election, said that rather than tweeting accusations, “it would be more helpful if he turned over any evidence he has,” and not comment further.

Sen. Susan Collins (R-ME) speaks to reporters in the Senate subway after a vote on Rick Perry for Energy Secretary March 2, 2017 in Washington, DC.

“The president has called for a congressional investigation into the allegations he made starting yesterday morning, so I would expect that he’s going to want to provide our committee with any evidence that he has,” Collins said.

“My own theory is that the Russians are determined to sow the seeds of discontent and doubt about the legitimacy of our democracy and other western democracies and that they were going to do that regardless of who was elected president, so it’s really important that we know what happened,” she said.

Sen. Mark Warner of Virginia, the ranking Democrat on the Intelligence Committee, said he believes the investigation underway will “get the information we need.” He said he expects to hear from former national security adviser Michael Flynn, who resigned after his contacts with Kislyak during the transition to Trump’s presidency were revealed.

Georgetown University law professor Paul Rothstein said an attack like Trump’s on a former president is “unprecedented. I am aware of no other one like this.”

Rothstein explained that the president himself could not legally order a wiretap but the FBI or the Justice Department could apply for a warrant if they could demonstrate to a judge that there was evidence giving rise to probable cause a crime has been or is being committed or spying is being done by a foreign agent and that a domestic wiretap would reveal it.

In the case of a possible foreign agent, the application would be to the FISA court, Rothstein said.

Contributing: Nicole Gaudiano