Cameron Joseph contributed reporting

A group of female Democratic senators on Wednesday called on Sen. Al Franken (D-MN) to resign from Congress, following weeks of mounting sexual misconduct allegations against the embattled lawmaker.

In a wave of statements and Twitter posts, at least 10 of Franken’s female colleagues called him out on Wednesday just after 11:30 a.m. EST: Sens. Kirsten Gillibrand (D-NY), Mazie Hirono (D-HI), Maggie Hassan (D-NH), Claire McCaskill (D-MO), Patty Murray (D-WA) Kamala Harris (D-CA), Tammy Baldwin (D-WI), Debbie Stabenow (D-MI) Heidi Heitkamp (D-ND) and Tammy Duckworth (D-IL). Sen. Bob Casey (D-PA) was the first male senator to call for his resignation.

Democratic aides familiar with the female senators’ discussions told TPM that they had been in ongoing talks about Franken’s future, and that Wednesday’s push “was a result of mounting frustrations over the increasing number of accusations.” But not all female Democratic senators were looped in.

Fellow Minnesota Sen. Amy Klobuchar (D-MN) spoke with Franken personally on Wednesday and said the congressman’s office plans to release a statement on Thursday. She said she’s “confident he will make the right decision.”

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. — Amy Klobuchar (@amyklobuchar) December 6, 2017

Gillibrand was the first senator to speak up, posting on Facebook that she was “shocked and disappointed to learn over the last few weeks that a colleague I am fond of personally has engaged in behavior towards women that is unacceptable” and said it was a “moment of reckoning” for those who have been accused of sexual harassment and assault.

“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,” she wrote. “In the wake of the election of President Trump, in just the last few months, our society is changing, and I encourage women and men to keep speaking up to continue this progress. At this moment, we need to speak hard truths or lose our chance to make lasting change.”

The others followed suit.

At least six women have gone public in recent weeks alleging Franken forcibly kissed them or groped them in the past. LA radio host Leeann Tweeden was the first to come forward, alleging the congressman aggressively kissed her when the two were rehearsing for a skit while on a USO tour in 2006 and groping her while she was sleeping. She released a photo with her statement, that appears to show Franken grabbing toward her chest while she slept.

Several others have spoken up since, saying Franken groped their butts during photo opportunities over the years. The most recent woman, a former Democratic congressional aide, came forward Wednesday alleging the senator forcibly kissed her in 2006 after the taping of his radio show.

When Tweeden went public, Franken apologized for the photo and said he remembered the rehearsal differently. He asked for the Senate Ethics Committee to launch a full investigation into the allegations against him. He has since apologized to the other women for making them feel disrespected, but has combatted many of their claims. On Wednesday, he told Politico that the actions alleged by the anonymous former congressional were “categorically not true.”

The allegations have been particularly jarring for Democrats who know Franken as a champion for legislation that supports survivors of sexual and domestic violence and workplace harassment. But many of his female and male colleagues said Wednesday that they think the mounting accusations are a sign of a problematic pattern of behavior by the congressman.

Hirono said in a statement that she “struggled with this decision” because she considers Franken a “friend,” but said she couldn’t excuse his behavior. She said TIME magazine’s decision to name “The Silence Breakers” their “Person of the Year” has brought to light something that “women have always known.”

“There are men among us who use their positions of power and influence to manipulate, harass, and assault women. What is new here is the women,” she said. “We are, all of us, speaking out, naming names and demanding that the harassers take responsibility for their behavior.”

Hassan also released a statement, saying it was “clear” Franken had engaged in a “pattern of egregious and unacceptable behavior.”

“We are experiencing a sea change in our culture that is long overdue, and we must continue working to empower all women and do everything we can to prevent sexual harassment, misconduct, and assault,” she said.

Harris, Baldwin, Stabenow and McCaskill joined the chorus by posting on Twitter, with Harris saying it would be the “best thing” for Franken to step down.

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. — Kamala Harris (@SenKamalaHarris) December 6, 2017

Al Franken should resign. — Claire McCaskill (@clairecmc) December 6, 2017

I believe it is best for Senator Franken to resign. — Sen. Tammy Baldwin (@SenatorBaldwin) December 6, 2017

Sexual harassment is unacceptable. I believe Senator Franken should do the right thing and resign. — Sen. Debbie Stabenow (@SenStabenow) December 6, 2017

Murray also said she thought there was enough evidence to show that Franken has a “deeply harmful, persistent problem” of sexual misconduct against women and said Congress could not “pick and choose based on political party or friendship who we call out.”

Sen. Patty Murray becomes the 5th female senator to call out Sen. Franken in the span of 10 minutes. pic.twitter.com/2lscdylfi4 — Marianna Sotomayor (@MariannaNBCNews) December 6, 2017

In a statement also shared on Twitter, Heitkamp said she was disappointed in Franken and said Congress “must commit to zero tolerance.”

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. Full statement: pic.twitter.com/4qrZB0mBTo — Sen. Heidi Heitkamp (@SenatorHeitkamp) December 6, 2017

Duckworth joined the ensemble a few hours later, releasing a similar statement of disappointment in her colleague’s behavior. She also thanked the accusers for raising their voices.

“Your courage and strength in driving this long-overdue national conversation is awe-inspiring,” she said. “As national leaders, we must hold ourselves to a higher standard—and we must lead by example to ensure every person is treated with the dignity and respect they deserve. This isn’t about Democrats or Republicans, it’s about our society. It’s about who we are as a people and the kind of country we want our daughters—and our sons—to grow up in.”

An aide to Sen. Elizabeth Warren (D-MA) told The Boston Globe that Warren called Franken privately on Wednesday to tell him he should resign. She has not yet confirmed that publicly.

Casey posted on Twitter and said he agreed with his female colleagues and that “we can’t just believe women when it’s convenient.” Sens. Joe Donnelly (D-IN), Michael Bennet (D-CO) and Dick Durbin (D-IL) also released statements on Twitter shortly after, asking Franken to step aside.

I agree with my colleagues who have stepped forward today and called on Senator Franken to resign. We can’t just believe women when it’s convenient. — Senator Bob Casey (@SenBobCasey) December 6, 2017

Joe is calling for Senator Franken to resign. pic.twitter.com/ff5i1rnhJs — Senator Joe Donnelly (@SenDonnelly) December 6, 2017

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. — Michael F. Bennet (@SenBennetCO) December 6, 2017

Senator Franken’s behavior was wrong. He has admitted to what he did. He should resign from the Senate. — Senator Dick Durbin (@SenatorDurbin) December 6, 2017

Sen. Patrick Leahy (D-VT) said later Wednesday afternoon that he had “just learned of the latest, disturbing allegation” against Franken and said he “has to step aside.”

“While the facts from case to case can differ, and while there are sound reasons for weighing evidence in such cases in a deliberate and carefully considered process, Senator Franken’s situation has become untenable,” he said in a statement. “I am concerned that even a prompt Ethics Committee investigation and recommendations will not come soon enough. He has to step aside. I hope as a nation that we are beginning to come to terms with the systemic problem of sexual harassment and assault, but we still have a long way to go.”

Former presidential candidate Sen. Bernie Sanders (D-VT) spoke out later Wednesday afternoon, echoing the other senators’ comments in a string of tweets.

Sen. Franken has said that he will be making an announcement about his political future tomorrow. The right thing is for him to resign. — Bernie Sanders (@SenSanders) December 6, 2017

We are now at a crossroads in American culture. And it is an important one. The way we treat women in our country has been abysmal in almost every way. — Bernie Sanders (@SenSanders) December 6, 2017

We are finally addressing the issue of sexual harassment, and we need to get it right. But the conversation we are having now is only the tip of the iceberg. — Bernie Sanders (@SenSanders) December 6, 2017

It needs to be an ongoing movement of women and men that includes a national discussion about sexism, sexual harassment, objectification, inequality and abuse of power. — Bernie Sanders (@SenSanders) December 6, 2017

Senate Minority Leader Chuck Schumer’s (D-NY) office did not immediately return TPM’s request for comment.

At least four House Democrats have also asked for his resignation, but Wednesday’s wave of calls was the first substantial move by Democratic members of the Senate to question their colleague’s future in Congress.