“It’s very disturbing,” Ms. Gillibrand said of Mr. Franken. “I was very disappointed. But it’s important that survivors are coming out and speaking truth to power and telling their stories.”

Earlier, she said she would give all the donations her campaign had received from Mr. Franken’s political action committee to Protect Our Defenders, which helps those assaulted in the military. She also introduced the “Me Too Congress Act” on Thursday to address yearslong and rampant sexual misconduct on Capitol Hill.

Ms. Gillibrand began a new push this week for legislation to authorize military prosecutors, rather than commanders, to decide which sexual assault cases should be brought to court, with the aim of encouraging more people to report crimes without fear of retaliation.

She was an early supporter of Mrs. Clinton’s 2016 presidential campaign and has spent countless hours raising money for Democratic women who run for office, citing Mrs. Clinton as a role model.

“In my adult life, politically, no one has inspired me to get off the sidelines and truly make a difference more than Hillary Clinton has,” Ms. Gillibrand said last year in an essay on why she was supporting Mrs. Clinton.

Ms. Gillibrand has also noted Mr. Clinton’s support for her own run for office. “I was lucky enough to receive guidance and mentorship from Hillary during that run, and was truly honored that President Bill Clinton campaigned for me in my first run for Congress in 2006,” she wrote in the same essay.