A Beltway PR firm known for its roster of influential liberal clients has shut down, reportedly after persistent complaints of “serial” sexual harassment against its founder and president. 

Trevor FitzGibbon, chief of FitzGibbon Media -- which has counted MoveOn.org, the AFL-CIO, NARAL, the Center for American Progress and WikiLeaks among its clients -- told FoxNews.com in a statement Friday that the allegations of sexual harassment, and even assault, are “a distraction,” and he was taking a “leave of absence.”

But he confirmed they made the "difficult decision" to close FitzGibbon Media. 

“I apologize to my team and our clients for the impact this closing will have on them,” he said. “I will work to once again regain the trust that was lost.” 

Allegations were swirling about the impetus for the abrupt shut-down, just days before the holiday break. It appears the move comes after staff members came forward with complaints, and expressed they could no longer work under FitzGibbon.

According to a tweet from Sean Carlson, the firm’s digital director, on Thursday, “(FitzGibbon Media) closed because we would no longer follow the leadership of a serial sexual harasser.”

In a lengthy story published by The Huffington Post Thursday, several former staffers also accused FitzGibbon of a long history of sexual harassment, including inappropriate behavior like encouraging women to send him photos of themselves and asking them for hugs. A prospective employee named Sierra Pedraja, 26, told members of the staff, and later The Huffington Post, that FitzGibbon allegedly tried to coax her into what she considered an inappropriate relationship in exchange for a job at the firm.

Pedraja showed the online news site several screen grabs of awkward conversations between her and FitzGibbon. Upon their first meeting, she contends, he asked her if she was open to having any fun when she was in town. “I knew exactly what he meant,” she told The Huffington Post. “I really wanted the job, but I didn’t want to embarrass him and mortify him ... So I gave a nervous laugh.” He allegedly reached out to her several times, commenting on her Facebook photos and asking for one himself, according to screen grabs obtained by reporters.

But the newly-let go staff says this was only the tip of the iceberg. According to reports, FitzGibbon had a history of harassment dating back to his previous employer, Fenton Communications. After breaking out on his own, he allegedly left a trail of complaints, according to a statement by the Fitzgibbon staffers. 

“Staffers reported over a half dozen incidents of sexual harassment and at least two involving sexual assault committed by Trevor FitzGibbon against his own employees,” according to the statement provided to FoxNews.com from associate vice president of media relations, Christina DiPasquale -- who confirmed that she, too, was a signatory. She said the statement was written by “the majority of staffers laid off due to Trevor's serial sexual assault of both staff and non-staff.”

The statement did not elaborate on the alleged incidents of assault, or whom they reported the incidents to, other than The Huffington Post. 

It said: “For decades, Trevor presented himself a champion of the progressive movement, claiming to support and respect women and feminist issues, from equal pay to reproductive rights, but his actions prove a hypocrisy so great that Fitzgibbon Media closed its doors today, as we could no longer continue working under his leadership.” 

It is not clear whether FitzGibbon faces legal problems at this time. A statement from the firm said the closing came “after much discussion and deliberations, and in consultation with legal counsel.”

Fitzgibbon’s brother Blair FitzGibbon said he was working with Trevor up until two years ago. He then broke off to begin his own media company in the D.C. area and has had nothing to do with his brother’s work since.

He would not directly confirm the allegations, but told FoxNews.com he was "just learning about these revelations in the news like others are." 

FoxNews.com's Kelley Vlahos contributed to this report.