Half a dozen female Democratic senators have called on Al Franken to resign, as another woman stepped forward to accuse the Minnesota Democrat of sexually inappropriate behavior. They were joined by the minority leader in the Senate, Chuck Schumer, and the national party chair, Tom Perez, who also called on Franken to step down.

Franken’s office said he would make a public statement – expected to include a response to the calls – on Thursday. One Democratic senator, Ron Wyden, said he expected Franken to “announce his resignation tomorrow”.

In Facebook posts, tweets and public statement, several Democrats urged their colleague to step aside amid widening accusations of sexual assault and misconduct against powerful men that have roiled Hollywood, Silicon Valley and Washington.

“I have spent a lot of time reflecting on Senator Franken’s behavior,” Senator Kirsten Gillibrand of New York, a longtime advocate for victims of sexual assault, said in a Facebook post that started the cascade of calls. “Enough is enough.”

Gillibrand was joined by Patty Murray of Washington, Mazie Hirono of Hawaii, Claire McCaskill of Missouri, Kamala Harris of California and Maggie Hassan of New Hampshire.

Those calls were swiftly echoed by other colleagues, including Dick Durbin, the No 2 Democrat in the Senate, as well as Tammy Baldwin of Wisconsin, Sherrod Brown of Ohio, Bob Casey of Pennsylvania, and Joe Donnelly of Indiana.

Tom Perez, the chair of the Democratic National Committee, also called on Franken to resign.

“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 said.

Perez’s remarks came less than 36 hours after the Republican National Committee renewed its support for Roy Moore, the Republican Senate candidate who is facing multiple allegations of inappropriate behavior with teenage girls and women, including sexual assault.

While many national Republicans have distanced themselves from the Alabama Republican, he has been endorsed by Donald Trump. The Senate majority leader, Mitch McConnell, who has called on Moore to drop out, has said the Alabama Republican would face an ethics investigation if elected.

McConnell issued a statement calling for Franken to step down: “The near daily barrage of allegations of sexual misconduct against Senator Franken are extremely concerning to all of us in the Senate. While the Senate ethics committee is reviewing these serious allegations, it now appears that Senator Franken has lost the support of his colleagues, and most importantly, his constituents. I do not believe he can effectively serve the people of Minnesota in the US Senate any longer.”

Hours later, the Senate minority leader, Chuck Schumer, weighed in to say he too believed Franken should resign. In a brief statement, Schumer said: “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.”

Franken, 66, who has been accused by multiple other women of groping or trying to forcibly kiss them, has apologized for his behavior and asked the Senate ethics committee to investigate him but the senators said elected officials must be held to a higher standard, putting his political future in question. Franken did not appear in the Senate on Monday.

“This institution has evolved over centuries, it’s evolved over my nearly three decades of service, and it’s evolving once more before our very eyes,” said Murray, a member of Democratic leadership.

“This current evolution is long overdue. It’s time for us as elected representatives to hold ourselves to a higher standard, to set an example, and to live a set of values that is truly representative and worthy of the Congress, our democracy, and our great country.”

Hirono tweeted: “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.”

Harris posted: “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.”

Earlier on Tuesday, Politico reported on a new allegation against Franken. A former Democratic congressional aide said the former comedian tried to forcibly kiss her after a taping of his radio show in 2006, as he was ramping up his campaign for the US Senate, according to Politico. The aide dodged his advance and alleged that Franken said as she left: “It’s my right as an entertainer.” Franken denied the accusation to Politico.

The calls for Franken to resign come one day after John Conyers, the longest-serving Democrat in Congress, resigned after allegations of sexual harassment. Conyers, who was the top Democrat on the House judiciary committee and spent over a half-century on Capitol Hill, had settled one claim of sexual harassment against him with taxpayer money and had been accused of misconduct by several other former staffers.

Two other members of Congress currently face allegations of sexual harassment: Republican Blake Farenthold of Texas and Democrat Ruben Kihuen of Nevada.