(CNN) -- San Diego Mayor Bob Filner's former spokeswoman sued him for sexual harassment Monday, calling Filner unfit "to hold any public office" and adding a new dimension to the scandal he faces.

Irene McCormack Jackson said she and other women were subjected to "crude and disgusting" comments and inappropriate touching by Filner. She said she resigned as Filner's communications director in June after deciding that the mayor would not change his behavior.

"I had to work and do my job in an atmosphere where women were viewed by Mayor Filner as sexual objects or stupid idiots," Jackson said. She said Filner asked her to work without underwear and made repeated sexual advances toward her.

"He is not fit to be mayor of our great city. He is not fit to hold any public office. A man who lacks character makes a mockery of his ideas," she said.

Filner has been battling allegations of sexual harassment for several weeks, but none of the women leveling those claims had come forward before Jackson filed suit in a state court Monday. Her lawyer, Gloria Allred, called on Filner to resign, telling reporters, "Apologies alone will not take care of this injustice."

In a statement issued Monday evening, Filner said he was "saddened" by the accusations, but "I remain committed to the people of San Diego and the work that needs to be done."

"Once due process is allowed to unfold, I am certain there will be a better understanding of this situation," he said, adding, "I humbly ask that through this vicious storm of controversy, people take a moment and temper their rush to judgment."

Filner said last week that he believes he will be vindicated by "a full presentation of the facts." But he has also acknowledged, "I need help," and added, "I'm clearly doing something wrong."

"I am embarrassed to admit that I have failed to fully respect the women who work for me and with me, and that at times I have intimidated them," Filner said in a statement earlier this month. "It's a good thing that behavior that would have been tolerated in the past is being called out in this generation for what it is: inappropriate and wrong."

Jackson's lawsuit names Filner and the city as defendants. San Diego City Attorney Jan Goldsmith said his office will defend the city but not Filner, who he said has hired his own lawyer.

Asked whether his office would urge Filner to resign, Goldsmith said, "There's enough legal issues to keep us busy. I'm not getting into the political ones."

The 70-year-old Filner served five terms in Congress before being elected mayor in 2012. Rep. Susan Davis, a San Diego-area congresswoman who served alongside Filner, joined calls for his resignation on Monday.

"Despite his inclusive vision for San Diego, Mayor Filner has lost the confidence of San Diegans to lead," Davis, a fellow Democrat, said in a written statement. "He has taken advantage of the trust the voters placed in him and lost both the promise and capacity to ignite positive change. His behavior, if not illegal, is reprehensible."

Davis said she and Filner "have never had a smooth relationship," but she "respected his passion for our city and his interest to change the way business is done."

"But all of that is now lost because he did not have enough passion for the city to curb his incomprehensible and unacceptable behavior," she said.

Another Democrat, former City Councilwoman Donna Frye, and two attorneys who say they represented accusers had leveled allegations against the mayor before Monday.

Jackson said her decision to resign was clinched after Filner's deputy chief of staff resigned in June. Filner "refused to listen to someone he had known for 35 years, and who told him explicitly, during a senior staff meeting, that his behavior with women was terrible and possibly illegal.

Filner "laughed it off," she said. She said Filner challenged her to provide one example of improper behavior; when she brought up his comments about wearing underwear, "He had no comeback," she said.

The San Diego Sheriff's Department has established a hotline for accusers, who are allowed to remain anonymous under California law. Since the phone number was announced Friday, the department has received calls, spokeswoman Jan Caldwell told CNN on Monday.

No further details were given.

CNN's Amanda Watts, Chuck Johnston and Greg Botelho contributed to this report.