Sen. Sherrod Brown, D-Ohio, called on the U.S. Senate to expel Sens. Ted Cruz, R-Texas, and Josh Hawley, R-Mo., if the senators refuse to resign in the aftermath of this week's siege on the Capitol.

"Both @HawleyMO and @SenTedCruz have betrayed their oaths of office and abetted a violent insurrection on our democracy," Brown wrote on Twitter. "I am calling for their immediate resignations. If they do not resign, the Senate must expel them."

Both Republican senators have faced bipartisan condemnation for their roles in opposing the ratification of Electoral College votes.

-ABC News' Trish Turner

Sen. Pat Toomey, R-Pa., said Saturday that he believes the president "committed impeachable offenses" after the violent siege on the Capitol this week by a pro-Trump mob.

"I have to say I do think the president’s behavior this week does disqualify him from serving," Toomey said on Fox News.

"I don't know what they are going to send over," he said of the House effort to draw up an article of impeachment. "And one of the things I am concerned about frankly, is whether the House would completely politicize something. I do think the president committed impeachable offenses, but I don't know what's going to land on the Senate floor, if anything," he added.

The Republican senator voted against the objections to counting the electoral votes from Arizona and Pennsylvania this week.

While the senator did not explicitly call for Trump's removal from office, Toomey's comments come amid increased calls by Republicans to hold the president accountable for Wednesday's riot. Sen. Lisa Murkowski, R-Alaska, and Rep. Adam Kinzinger, R-Ill., have both called for Trump to vacate the presidency.

West Virginia Delegate Derrick Evans resigned Saturday after being charged for his involvement in the violent siege of the U.S. Capitol this week.

“The past few days have certainly been a difficult time for my family, colleagues and myself, so I feel it’s best at this point to resign my seat in the House and focus on my personal situation and those I love,” Evans said in a statement.

The West Virginia Republican was taken into custody Friday and charged with one count of knowingly entering or remaining in any restricted building or grounds without lawful authority and one count of violent entry and disorderly conduct on Capitol Grounds," according to the criminal complaint.

Evans had recorded himself and other supporters of Trump rushing into the Capitol after breaching the security barrier Wednesday. He has since deleted the video from his social media accounts.

-ABC News' Lucien Bruggeman and Joshua Hoyos

In December, while a signature match audit was ongoing in one Georgia county, President Donald Trump phoned a chief investigator in Secretary of State Brad Raffensperger's office asking the official to "find the fraud" and telling this person they would be a "national hero" for it, an individual familiar with the matter confirmed to ABC News.

The Washington Post was first to report on the lengthy phone call, which occurred before Trump's stunning, hourlong phone conversation with Raffensperger in which the president ranted about baseless allegations of election fraud and pressured Georgia's top elections official to "find" enough votes to deliver him a win in the Peach State.

That call, which took place on Jan. 2, is cited in the draft article of impeachment against the president that Democrats could introduce as early as Monday.

Deputy Secretary of State Jordan Fuchs confirmed the call between Trump and the chief investigator took place without offering details, saying only: "The secretary and the secretary of state's office can confirm that the call did happen."

The White House declined to comment.

-ABC News' Quinn Scanlan

House Speaker Nancy Pelosi, in a new letter to Democrats on Saturday, asked members to prepare to return to Washington this week -- another signal that the House could take up and pass the impeachment article to the Senate after it is formally introduced on Monday.

Pelosi thanked fellow Democratic representatives for speaking with her on a conference call Friday and said she was taking their considerations into account. She did not specifically mention voting on impeachment in the letter, though.

"Since that call, I have received scores of communications from Members expressing your views about how we go forward and regarding a strong presence of our Caucus in the Capitol," she wrote. "Over the last few days, I have discussed your views with Constitutional lawyers, both inside and outside the Congress, to consider the parliamentary and constitutional options available to us."

"From what I have heard from Members, and from the deluge that I have received from the public, it is clear that, once again, the Times Have Found Us to save our democracy," Pelosi added in the letter. "We will be proceeding with meetings with Members and Constitutional experts and others. I continue to welcome your comments. I urge you to be prepared to return to Washington this week."

While Democrats are hopeful Republicans will back their effort, none have come out and said they would back the charge as drafted.

Pelosi said at a press conference on Thursday, "If the Vice President and Cabinet do not act [on the 25th Amendment], the Congress may be prepared to move forward with impeachment."

Some Democrats planned to connect with Republican colleagues this weekend to gauge their support and encourage them to back the effort.

-ABC News' Benjamin Siegel