On Sunday, U.S. Sen. Susan Collins, R-Maine, said President Donald Trump should turn over tapes of conversations he had with fired FBI Director James Comey — if they exist.

“He should voluntarily turn them over not only to the Senate Intelligence Committee, but to the special counsel,” Collins told Brianna Keilar on CNN’s “State of the Union.”

“I don’t understand why the president just doesn’t clear this matter up once and for all,” she added.

Almost a month after suggesting that he recorded conversations with Comey in the White House, writing in an early-morning Twitter message that “Comey better hope that there are no ‘tapes’ of our conversations,” the president has yet to definitely answer the question of whether any such tapes even exist.

“I’ll tell you about that maybe sometime in the very near future,” Trump told reporters Friday when asked about the existence of any tapes.

Collins, a member of the Senate Select Committee on Intelligence, joins Republicans on the House Intelligence Committee who, with their Democratic colleagues, sent a letter to the White House on Friday demanding the president turn over any recordings with Comey within two weeks.

In her interview on Sunday, Collins added that she would support a subpoena being issued if the White House stonewalled, though she said such an order would likely come from special counsel Robert Mueller and not from the Senate committee.

“I would be fine with issuing a subpoena,” Collins said.

On Thursday, Comey testified to the Senate that, in a Feb. 14 conversation in the Oval Office, Trump asked Comey to “see your way clear to letting” go of the FBI investigation into Trump’s former national security adviser, Michael Flynn.

Collins said such a conversation was “clearly wrong on the president’s part,” stopping short of calling it obstruction of justice, a step few Republicans or Democrats in Congress were willing to make on the Sunday morning political shows following Comey’s testimony.

“Look, when it comes to something like obstruction, there’s a serious legal standard,” Senate Minority Leader Charles E. Schumer, D-New York, said on CBS’s “Face the Nation” when asked if Comey made a case for obstruction of justice. “A good prosecutor looks at the facts and sees if it meets that standard. I’m not going to speculate about that. That’s in prosecutor Mueller’s hands.”

After calling Trump’s conversations with Comey before firing him “very inappropriate,” U.S. Sen. James Lankford, R-Oklahoma, argued that the president’s actions did not rise to the level of obstruction.

“The way that it was handled, with no follow-up, with no other press, with no other return to that topic, It looks like what I called a pretty light touch” Lankford also said on “Face the Nation” in reference to the Feb. 14 conversation. “If this is trying to interfere in a process of any investigation, it doesn’t seem like it was, one, very effective and, two, it came up more than once in a conversation.”