Update: Rep. Eric Swalwell said Monday, April 13, that he plans to resign from Congress.

Democratic Rep. Eric Swalwell suspended his bid for California governor on Sunday as he faced growing pressure to end his campaign amid allegations of sexual assault. 

"I am suspending my campaign for Governor," Swalwell wrote on social media. "To my family, staff, friends, and supporters, I am deeply sorry for mistakes in judgment I've made in my past. I will fight the serious, false allegations that have been made — but that's my fight, not a campaign's."

Swalwell denied the allegations Friday after a former staffer accused him of sexually assaulting her twice when she was too drunk to consent, among other alleged misconduct. 

Swalwell called the allegations "false" and suggested they were politically motivated. He threatened to take legal action against the unnamed woman, who detailed the alleged encounters to the San Francisco Chronicle, which published a story Friday. 

The calls from Democrats to end his campaign were swift. Swalwell, who had won the backing of many of the state's top Democrats, lost their support as they expressed horror at the accusations. 

In a statement Friday night, House Democratic leaders had called for Swalwell to immediately end his campaign, but stopped short of urging him to resign from Congress. 

"This is unacceptable of anyone — certainly not an elected official — and must be taken seriously," House Minority Leader Hakeem Jeffries of New York, Whip Katherine Clark of Massachusetts and Caucus Chair Pete Aguilar of California said. "All perpetrators of sexual assault and harassment must be held accountable."

California's two Democratic senators, Adam Schiff and Alex Padilla, also called on Swalwell to withdraw. Schiff said he was "deeply distressed" by the accusations.

Dozens of Swalwell's former staffers called for him to drop out of the race and also resign from Congress, writing in a letter sent over the weekend, "We stand unequivocally with our colleague, who showed extraordinary courage in coming forward to share her truth. We believe her."

Swalwell is facing the possibility of an expulsion vote in the House. Rep. Anna Paulina Luna, a Florida Republican, announced plans to force a vote to expel Swalwell over the allegations, and a vote could come as soon as midweek.

The California Democrat is also facing an investigation from the Manhattan District Attorney's Office, which confirmed to CBS News on Sunday that it was looking into the allegations.

The district attorney's office asked any survivors and those with relevant information to contact the office, saying in a statement, "Our specially trained prosecutors, investigators, and counselors are well-equipped to help you in a trauma-informed, survivor-centered manner."