House Minority Leader Nancy Pelosi and House Speaker Paul Ryan have called on Rep. John Conyers, D-Mich., to step down amid multiple allegations of sexual harassment from former staffers.

"The allegations against Conyers, we have learned more since Sunday, are serious, disappointing and very credible," Pelosi, D-Calif., told reporters on Thursday. "The brave women who came forward are owed justice…Congressman Conyers should resign."

"I heard what she said this morning on NBC. No one should have to go through something like that, let alone here in Congress," Ryan told reporters separately. "So yes, I think he should resign, and I think he should resign immediately."

Conyers, 88, denies the allegations, and was hospitalized overnight due to stress, according to political consultant Sam Riddle, who told reporters in Detroit he had spoken with Conyers' wife, Monica.

"I pray for Congressman Conyers and his family, and wish them well," Pelosi said. "However, Congressman Conyers must resign."

Conyers is the longest-serving member of Congress, and was first elected to represent the Detroit area in 1965. Allegations against him first arose last week, when Buzzfeed News published documents outlining a $27,000 settlement Conyers paid to a former staffer who accused him of firing her after she rejected his persistent sexual advances.

The accuser, Marion Brown, spoke publicly for the first time on NBC's "Today" show Thursday, describing years of unwanted attention from Conyers.

"Some of the things that he did, it was sexual harassment," she said . "Violating my body, propositioning me, inviting me to hotels with the guise of discussing business, and then propositioning for sex. He just violated my body. He has touched me in different ways, and it was very uncomfortable and very unprofessional."

Brown was initially barred from speaking about her complaint by a nondisclosure agreement, but she said on Thursday that Conyers' denial of the allegations prompted her to go public.

"Congressman Conyers came out and called me a liar, basically," Brown said. "So I'm here to say that I'm not a liar."

Pelosi had been pilloried for her initial remarks on Sunday that came across as defending Conyers , whom she called an "icon in our country" for his work in civil rights and said deserved the benefit of due process. At the time, she said his accusers "have not really come forward."

She has since done an about-face, meeting with Melanie Sloan, one of the women who says Conyers verbally abused her and acted inappropriately, although she did not accuse him of sexual harassment.

"Ms. Sloan told me that she had publicly discussed distressing experiences while on his staff," Pelosi said in a statement issued Monday. "I find the behavior Ms. Sloan described unacceptable and disappointing. I believe what Ms. Sloan has told me."