In an open letter to the mayor, Boxer called on Filner to resign his office and “get the help you need as a private citizen.”

“Bob, you must resign because you have betrayed the trust of the women you have victimized, the San Diegans you represent and the people you have worked with throughout your decades in public life,” Boxer wrote.

Filner, a former Democratic member of Congress, has been accused of unwanted advances by 14 women. One, his former communications director, is suing Filner and the city of San Diego.

Boxer, along with several other lawmakers, has already publicly called on Filner to resign. House Minority Leader Nancy Pelosi (D-Calif.) called the mayor’s actions “reprehensible” and “disrespectful of women,” while Rep. Debbie Wasserman Schultz (D-Fla.) said in a statement that she is “personally offended” by his behavior.

Boxer has worked in the Senate to combat sexual violence and harassment, most recently teaming up with Sen. Kirsten GillibrandKirsten Elizabeth GillibrandSenators near deal on sexual harassment policy change Overnight Health Care — Sponsored by PCMA — Trump hits federally funded clinics with new abortion restrictions Dem senators ask drug companies to list prices in ads MORE (D-N.Y.) in an effort to fight sexual assaults in the military.

In the Friday letter, Boxer called Filner’s actions “shocking” and added that the latest revelations regarding his behavior toward women recovering from sexual assault “have shaken me to my core.”

“Bob, you have already hurt so many people,” Boxer wrote. “To avoid hurting your victims and the people of San Diego more than you already have, you should step down immediately.”

Filner announced late last month that he would take a leave of absence but did not say he would resign.

He has said the city failed to provide state-required sexual harassment training, though a contradicting report states that Filner’s office canceled the session.