The spiritual leader of an upstate New York self-help group pleaded not guilty on Monday to newly filed child pornography charges at a hearing where it became clear that his co-defendants are trying to avoid going to trial with him next month.

Keith Raniere was charged last week with exploiting a child and possessing child pornography. He had previously pleaded not guilty to charges accusing him of operating a secret society within his NXIVM group that forced women "slaves" to have unwanted sex with him and branded them with his initials.

Assistant U.S. Attorney Moira Penza told a judge on Monday that the government is in "active plea negotiations" with Allison Mack, best known for playing a teenage friend of Superman on the "Smallville" TV series, and two other defendants in the sex-trafficking case. Additionally, defense attorney Mark Geragos said that his client, Seagram liquor fortune heiress Clare Bronfman, will be asking for a separate trial on charges she bank-rolled the Albany-based group that has been compared to a cult. Bronfman and Mack have previously denied the charges.

"We don't need to be the collateral damage," Geragos said.

It remains unclear whether Raniere will face the child porn charges at the upcoming trial in federal court in Brooklyn or if he will be tried on them separately in upstate New York at a later date. His lawyers have accused prosecutors of tainting the jury pool by making the sensational accusations with the start of jury selection only three weeks away.

"The gravity of these charges is monumental," one the attorneys, Marc Agnifilo, said Monday.

U.S. District Judge Nicholas Garaufis told the defense lawyers that he wants them to file briefs by the end of the week before he would rule on how to go forward.

The prospect that the 58-year-old Raniere — known as "Vanguard" within his group — could stand trial alone began to take shape last week when NXIVM's chief executive, Nancy Salzman, became the first defendant to plead guilty. She admitted to stealing identities of the group's critics and hacking into their email accounts, as well as conspiring to doctor videotapes before they were turned over to plaintiffs in a New Jersey lawsuit against the group.

According to a government filing, the new charges against Raniere involve "a 15-year-old girl who was employed by Nancy Salzman and who — ten years later — became Raniere's first-line 'slave'" and "a child whose sexual relationship with Raniere was known to, and facilitated by, members of the Enterprise."

Regarding the teen, the papers say the evidence includes child pornography Raniere created and possessed and "electronic communications between the victim and Raniere reflecting their sexual relationship and indicating that it began when she was fifteen years old."

Raniere has denied the allegations. He's been jailed without bail since being brought to the U.S. in 2018 following his arrest in Mexico.