Sen. Al Franken, D-Minn., said that he asked former FBI Director James Comey to investigate whether Attorney General Jeff Sessions met a third undisclosed time with Russian Ambassador Sergei Kislyak during the 2016 presidential campaign.

A report from CNN said congressional investigators were looking into a possible meeting on April 27, 2016, at the Mayflower Hotel in Washington, D.C.

During an appearance on MSNBC, Franken said he and a colleague, Sen. Patrick Leahy, D-Vt., sent a "private letter" to then-FBI Director James Comey asking for an investigation into the "fact Sessions had met other times with Russians, including this meeting that we're talking about in the Mayflower." He did not say when exactly the letter was delivered.

Comey, who was fired by President Trump last month, is expected to testify before Congress next week.

In March, Sessions had gotten into trouble when it was reported that he had two meetings with Kislyak during the campaign, which contradicted statements in his January confirmation hearing. Sessions had testified he did not have any communications with the Russians during the campaign.

This meeting at the Mayflower would be yet another undisclosed meeting with Kislyak. Franken made it clear that at the time of sending the letter that he was aware of a possible meeting at the Mayflower and that from his understanding Sessions can plausibly deny remembering it took place.

"Now it had been characterized one way, but we had some reason to believe that it — that wasn't the case," Franken said. "It had been described in a way that he could plausibly say I don't remember that. But what's coming out today, I believe, is that that may not be the case. And if this the true, that would be extremely disturbing."

After the CNN report came out, Sarah Isgur Flores, spokesperson for the department, issued a statement slamming the network and denying the meeting took place.

"It is unfortunate that anonymous sources whose credibility will never face public scrutiny are continuously trying to hinder that process by peddling false stories to the mainstream media," she said. "The facts haven't changed; the then-Senator did not have any private or side conversations with any Russian officials at the Mayflower Hotel."