WASHINGTON — Vice President Mike Pence said he was never part of discussions to remove President Trump from office and would take a lie-detector test “in a heartbeat” to prove that he was not the author of last week’s anonymous New York Times op-ed, who claimed to be part of a resistance movement within the Trump administration.

In interviews with “Fox News Sunday” and CBS’ “Face the Nation” that aired Sunday, Pence also said that he is “100 percent certain” that no one from his staff authored the op-ed and that he would be “more than willing” to sit down for an interview with special counsel Robert Mueller III as part of his ongoing Russia probe.

The appearances by Pence come as Trump has stepped up his calls for the Justice Department to investigate the author of the piece, which described a “two-track presidency” in which some senior aides are actively working to thwart Trump’s “misguided impulses” and have even discussed removing the president from office via the 25th Amendment.

They also come as former President Barack Obama has stepped forward to harshly criticize Trump and Republican politics, comparing Trump in a speech Friday to demagogues around the world who exploit “a politics of fear and resentment and retrenchment.”

Asked by “Face the Nation” host Margaret Brennan whether he had participated in any discussions with other Cabinet members about removing Trump from office, Pence replied, “No. Never. And why would we be, Margaret?”

He argued that the op-ed was “just an obvious attempt to distract attention from this booming economy and Trump’s record of success.”

In the interview with Fox News Channel’s Chris Wallace, Pence denied that he was the author of the op-ed and said he would gladly submit to a lie-detector test to prove it.

“I would agree to take it in a heartbeat and would submit to any review the administration wanted to do,” he told Wallace. But he declined to say whether he believes all top officials should be made to do the same, saying it was a decision for Trump to make.

In recent days, Trump has repeatedly said that he believes Attorney General Jeff Sessions should launch an investigation to find out who the author of the piece was, citing national security grounds.

Pence declined to say what, if any, law the author of the piece might have broken but maintained in his interview on “Fox News Sunday” that Trump’s “concern is that this individual may have responsibilities in the area of national security.”

Several other administration officials and congressional Republicans also spoke out on the Sunday morning news shows against the writer of the anonymous op-ed.

House Majority Leader Kevin McCarthy, R-Calif., argued in a Fox News appearance that the piece served as proof of a “deep state” seeking to create a constitutional crises.

“We have a Constitution. We have a responsibility to uphold. This individual thinks they are smarter than the voters of America, and they are going to change the course,” he said on “Sunday Morning Futures.” “This person is a coward. If this person really believed in their convictions, put their name on it, stand up and resign.”

Kellyanne Conway, counselor to the president, said in an appearance on CNN’s “State of the Union” that she believes the author of the piece “is going to suss himself or herself out.”

“I think cowards are like criminals. Eventually, they confess to the wrong person: ‘Shh. It was me, but don’t tell anyone.’ And, of course, the person will tell someone,” Conway said.

Some Democrats, meanwhile, argued that the op-ed and Trump’s response to it are proof that he is not fit to serve.

“Does this president not understand that the Justice Department is not a tool of his own personal power?” Sen. Mark R. Warner, D-Va., said on CNN in response to Trump’s recent statements calling on Sessions to investigate.

“That is one of the reasons why I think you’re seeing not only Republican members, but what appears to be a lot of folks in the White House, have real concerns about this president’s stability,” Warner added.

The vice president declined to speculate on whether someone had purposely inserted the word “lodestar” into the New York Times op-ed to set him up, telling Wallace simply, “I wouldn’t know.” Pence has frequently used the word in his speeches.