Updated: 6:30 p.m. | Posted: 10:05 a.m.
At least 28 Democratic senators and the Democratic National Committee chair are calling for Sen. Al Franken to resign.
Their calls come the same day Franken denied a new sexual misconduct accusation that came from a former Democratic congressional aide that he tried to forcibly kiss her after a taping of his radio show in 2006.
Now over half of the 46 Democrats in the Senate are calling for Franken to step down.
Sen. Amy Klobuchar tweeted a response to the news on Wednesday afternoon: "Sexual harassment is unacceptable. This morning I spoke with Senator Franken and, as you know, he will be making an announcement about his future tomorrow morning. I am confident he will make the right decision."
Minnesota Democratic Reps. Tim Walz and Collin Peterson both called for Franken to resign, as did Senate Majority Leader Mitch McConnell.
Fourth District Rep. Betty McCollum also released a statement but came short of asking for Franken to leave the Senate.
In an interview with MPR News, McCollum did say that if Franken does resign she wouldn't accept an offer to fill his seat — a position political observers have put her on the short list for.
Both independents in the Senate — Bernie Sanders and Angus King — have asked for Franken to resign.
As did DNC chair Tom Perez: "Everyone must share the responsibility of building a culture of trust and respect for women in every industry and workplace, and that includes our party," Perez tweeted.
Franken's office says the senator will make a statement Thursday.
Franken said Wednesday in a statement that the latest allegation, reported by Politico, was "categorically not true." Politico said it's withholding the aide's name to "protect her identity."
According to Politico, the woman said Franken pursued her after her boss had left and she was collecting her belongings. She said she ducked to avoid his lips, and that Franken told her: "It's my right as an entertainer."
Franken, in his statement, said the idea he would claim such conduct as a right as an entertainer was "preposterous."
The senator is facing a Senate Ethics Committee investigation into previous claims by several other women that he groped them or sought to forcibly kiss them.
"This allegation is categorically not true and the idea that I would claim this as my right as an entertainer is preposterous," Franken said. "I look forward to fully cooperating with the ongoing ethics committee investigation."
The allegations against Franken began in mid-November when Los Angeles radio anchor Leeann Tweeden accused him of forcibly kissing her during a 2006 USO tour.
Several other allegations have followed, including a woman who says that Franken put his hand on her buttocks during a picture pose at the Minnesota State Fair in 2010. An Army veteran also alleged Franken cupped her breast during a photo op on a USO tour in 2003. Two additional women also made anonymous claims against Franken in a Huffington Post article.
In an interview with MPR News' Cathy Wurzer on Nov. 26, Franken said he was taking responsibility for his behavior.
"I have been reflecting on this," the two-term senator said. "I want to be a better man."
Here is a list of the Democratic senators who have called on Franken to resign:
Sen. Chuck Schumer, D-N.Y.
"I consider Senator Franken a dear friend and greatly respect his accomplishments, but he has a higher obligation to his constituents and the Senate, and he should step down immediately."
Sen. Tammy Baldwin, D-Wis.
"I believe it is best for Senator Franken to resign."
Sen. Michael Bennet, D-Colo.
"Sexual harassment and misconduct are never acceptable. I understand Senator Franken will make an announcement tomorrow morning, and I'm confident he'll do the right thing and step aside."
Sen. Sherrod Brown, D-Ohio
"I have listened to my female colleagues, to women I work with and women in my life. And I agree the time has come for Senator Franken to step aside."
Sen. Maria Cantwell, D-Wash.
"Senator Franken's actions are disturbing, egregious, and demonstrate a pattern of serious misconduct and abuse. It is time for Senator Franken to resign from office."
Sen. Tom Carper, D-Del.
"Al Franken has been a friend to many in the Senate -- Republicans, Democrats and Independents alike -- but these allegations are deeply troubling, especially as the number has grown. I believe it's time for him to resign."
Sen. Bob Casey, D-Pa.
"I agree with my colleagues who have stepped forward and called on Senator Franken to resign. We can't just believe women when it's convenient."
Sen. Joe Donnelly, D-Ind.
"Senator Franken's conduct and behavior are unacceptable and he should resign."
Sen. Tammy Duckworth, D-Ill.
"I am deeply disappointed by Senator Franken's behavior. He must step aside."
Sen. Dick Durbin, D-Ill., No. 2 Democrat in the Senate
"Senator Franken's behavior was wrong. He has admitted to what he did. He should resign from the Senate."
Sen. Dianne Feinstein, D-Calif.
"It's clear the American people don't look lightly on these kinds of actions, no matter who they're committed by, and the number of complaints against Senator Franken is a concern. I think resignation is the right thing for him to do."
Sen. Kirsten Gillibrand, D-N.Y.
"While Senator Franken is entitled to have the Ethics Committee conclude its review, I believe it would be better for our country if he sent a clear message that any kind of mistreatment of women in our society isn't acceptable by stepping aside to let someone else serve."
Sen. Kamala Harris, D-Calif.
"Sexual harassment and misconduct should not be allowed by anyone and should not occur anywhere. I believe the best thing for Senator Franken to do is step down."
Sen. Maggie Hassan, D-N.H.
"It is clear that Al Franken has engaged in a pattern of egregious and unacceptable behavior toward women. He should resign."
Sen. Martin Heinrich, D-N.M.
"Senator Franken needs to step down and we all need to do more to make clear that sexual harassment and assault are unacceptable."
Sen. Heidi Heitkamp, D-N.D.
"We must commit to zero tolerance - which is where I believe we as a country and Congress should be - and that means Senator Franken should step down."
Sen. Mazie Hirono D-Hawaii
"Today, I am calling on my colleague Al Franken to step aside. I've struggled with this decision because he's been a good Senator and I consider him a friend. But that cannot excuse his behavior and his mistreatment of women."
Sen. Patrick Leahy, D-Vt.
"Senator Franken's situation has become untenable. I am concerned that even a prompt Ethics Committee investigation and recommendations will not come soon enough. He has to step aside."
Sen. Ed Markey, D-Mass.
"I join my colleagues in calling for Senator Franken to step aside and resign. Sexual harassment is unacceptable, completely inappropriate and cannot be tolerated."
Sen. Claire McCaskill, D-Mo.
"Al Franken should resign."
Sen. Jeff Merkley, D-Ore.
"Senator Franken has said he will make an announcement tomorrow, and I hope that he will do the right thing. It is in the best interest of our country for him to step aside."
Sen. Patty Murray, D-Wash., the No 3. Democrat in the Senate
"I'm shocked and appalled by Senator Franken's behavior. It's clear to me that this has been a deeply harmful, persistent problem and a clear pattern over a long period of time. It's time for him to step aside."
Sen. Gary Peters D-Mich.
"I think the time has come for Senator Franken to step down"
Sen. Debbie Stabenow, D-Mich.
"Sexual harassment is unacceptable. I believe Senator Franken should do the right thing and resign."
Sen. Tom Udall, D-N.M.
"Senator Franken should send a strong message that sexual misconduct is unacceptable in any setting and step down."
Sen. Jon Tester, D-MT.
"Elected officials must be held to a high standard, Al Franken is no exception. It's time for him to step down."
Sen. Ron Wyden, D-Ore.
"I expect that Senator Franken will announce his resignation tomorrow. It is the right thing to do given this series of serious allegations."
Sen. Cory Booker, D-N.J.
"I think it's time that he steps down. And this is an opportunity for him to speak to the larger issues that are clearly being evident, not only for his life, but also what's going on in American culture."
The Associated Press and NPR contributed to this story.
Editor's note: This story has been updated to show that Joe Donnelly represents Indiana in the Senate.