The aggressive response by Mr. Biden’s aides represents the latest indication of what they said over the weekend: that he will not be dissuaded by the allegations from entering the presidential race.
The challenge for Mr. Biden now, though, is that Ms. Flores is no longer alone in speaking out.
In her interview with the Courant, Ms. Lappos said the encounter that made her uncomfortable occurred at a fund-raiser in 2009, when she was working as a congressional aide to Representative Jim Himes of Connecticut.
“There’s absolutely a line of decency,” she told the Courant. “There’s a line of respect. Crossing that line is not grandfatherly. It’s not cultural. It’s not affection. It’s sexism or misogyny.”
She said she “never filed a complaint, to be honest, because he was the vice president. I was a nobody.”
The office of Senator Chris Murphy of Connecticut confirmed Monday that the event described in the Courant article took place and that Mr. Murphy, who was a congressman at the time, attended it.
The recent scrutiny of Mr. Biden’s physical behavior began on Friday when Ms. Flores, a Democrat, published an essay in New York Magazine’s The Cut, which described an encounter with Mr. Biden in 2014 that she described as mortifying.
In the essay, she wrote that Mr. Biden had come to a rally to help her fledgling campaign for lieutenant governor of Nevada and had come up behind her, touched her and planted “a big slow kiss” on the back of her head. Mr. Biden, in a statement Friday, said he did not believe he acted inappropriately, but pledged to listen to any accuser.
Since the essay published, Ms. Flores, 39, has praised Mr. Biden for being willing to listen to concerns and clarify his intentions. But she has said she finds it hard to believe that Mr. Biden could not have been aware of how he made her and other women feel and has called his behavior “completely inappropriate.