Larry Nassar, the former USA Gymnastics team doctor convicted of sexually assaulting hundreds of athletes, was in stable condition Monday after being stabbed multiple times by another inmate, a prison union official said.

Nassar, 59, was attacked on Sunday afternoon at the federal USP Coleman II prison in Sumterville, Florida, where he is serving his sentence, Joe Rojas, the president of the local correctional officers union, told AFP.

The disgraced physician was stabbed twice in the neck, six times in the chest and twice in the back, Rojas said.

"He's in stable condition last I heard," Rojas said.

Nassar pleaded guilty in late 2017 and early 2018 to sexually assaulting athletes while working as a sports medicine doctor at USA Gymnastics and Michigan State University and was sentenced to up to 175 years in prison.

Hundreds of women -- including Olympic gold medalists Simone Biles, Aly Raisman and McKayla Maroney -- have accused Nassar of sexually abusing them during his career of more than two decades.

The Bureau of Prisons (BoP) declined to confirm for "privacy" reasons that Nassar had been attacked but in response to a query about him said "an inmate" had been assaulted at 2:35 pm on Sunday at the Coleman prison and taken to a local hospital.

"Responding staff immediately initiated life-saving measures," the BoP said in a statement. "Staff requested emergency medical services and life-saving efforts continued.

"The Federal Bureau of Investigation was notified," the BoP said, and an "internal investigation is ongoing."

Nassar's victims reached a $380 million settlement with USA Gymnastics in 2021, one of the largest ever recorded for victims of sex abuse.

USA Gymnastics filed for bankruptcy in 2018 after a tidal wave of allegations against Nassar swamped the organization.

Michigan State University reached a $500 million settlement with hundreds of Nassar's victims in 2018.

The prison where Nassar is serving his sentence is a high security facility and currently houses 1,214 male offenders, according to the BoP.

Rojas, the prison union official, said the penitentiary is currently experiencing a "severe staffing crisis."

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