House Speaker Nancy Pelosi, D-Calif., is withholding the two articles of impeachment passed in the House until she gets "assurances from the Senate," Rep. Eric Swalwell, D-Calif., said Thursday.

Appearing on "Outnumbered: Overtime" with host Harris Faulkner, the former 2020 presidential candidate said that Pelosi wants to make sure that when the articles are sent over, there's no "predetermined rigged outcome."

"This is about fairness, and she hasn't spoken to specific witnesses. She's spoken to a fair trial," he said.

"I think the surprise is that Senator [Mitch] McConnell [R-Ky.] is not representing fairness because he is admitting that he is anything but impartial," said Swalwell.

MCCONNELL RIPS PELOSI FOR IMPEACHMENT DELAY, SAYS DEMS 'AFRAID' TO TRANSMIT 'SHODDY' ARTICLES

McConnell tore into Pelosi Thursday morning for what he called “shoddy work” and said Democrats may be “too afraid” to send the articles to the Senate.

Calling the development "comical," he said Democrats who stressed the urgency of the process now seem "content to sit on their hands."

"Looks like the prosecutors are getting cold feet," the GOP leader mused.

In a press conference later Thursday, Pelosi sought to clarify that her side is just waiting to see what the process will be in the Senate, so they can choose their trial “managers,” who would essentially serve as prosecutors.

The speaker also made clear that she did not intend to name the managers until they understand the “arena” in the Senate. And she fired back at McConnell, suggesting he’s a “rogue leader.”

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"Trials do have witnesses and I thought it was interesting that in 1999 Senator McConnell went on another television network and said, as it related to the Clinton impeachment trial, that the Senate trial then should have witnesses. He said trials have witnesses," Swalwell said. "He should follow the advice he gave then because it was right then and it's true now."

"It has not been 24 hours since we passed them," he added. "So, she wants assurances from the Senate, that's not unreasonable."

Fox News' Adam Shaw contributed to this report.