McKayla Maroney alleges past abuses by Larry Nassar as early as 13

— -- McKayla Maroney, a two-time Olympic medalist, has alleged that she was abused as early as age 13 by former Michigan State and USA Gymnastics doctor Larry Nassar, who already faces 22 counts of first-degree criminal sexual conduct and could receive a sentence of life in prison.

Maroney, now 21, helped the "Fierce Five" U.S. women's gymnastics team to the gold medal at the 2012 Summer Games in London. She spoke out early Wednesday as part of the "Me too" movement on Twitter, saying, "Silence has given the wrong people power for too long, and it's time to take our power back."

Nassar was involved with USA Gymnastics for nearly three decades as a trainer and national medical coordinator, a role that led him to treat the country's elite gymnasts at four separate Olympic Games.

"Dr. Nassar told me that I was receiving 'medically necessary treatment that he had been performing on patients for over 30 years,'" Maroney wrote. "It started when I was 13 years old, at one of my first National Team training camps, in Texas, and it didn't end until I left the sport. It seemed whenever and wherever this man could find the chance, I was 'treated.'

"It happened in London before my team and I won the gold medal, and it happened before I won my silver [in vault in London]."

Maroney also wrote that when she was 15, Nassar gave her a sleeping pill during an all-day flight to Tokyo and that she woke up alone with him in his hotel room.

"For me, the scariest night of my life happened when I was 15 years old," Maroney wrote in her Twitter post. "... He'd given me a sleeping pill for the flight, and the next thing I know, I was all alone with him in his hotel room getting a 'treatment.' I thought I was going to die that night."

Attorneys for Nassar had no comment when reached by The Associated Press. USA Gymnastics also had no immediate comment.

Attorneys representing 125 women who are suing Nassar agreed in August to take the cases to mediation, a step that could result in a settlement.

The plaintiffs are also suing USA Gymnastics, Michigan State and other defendants. Attorneys have said that more women are expected to join the lawsuits.

It is not known whether Maroney is part of those lawsuits.

Nassar has already pleaded guilty to federal child pornography charges and is in jail, awaiting a Nov. 27 sentencing in that case.

He also faces charges in state court in Michigan, largely related to allegations that he digitally penetrated women during medical exams for his own sexual gratification. If convicted on any one of the 22 counts of first-degree criminal sexual conduct, Nassar could be sentenced to life in prison.

Until Maroney, Jamie Dantzscher, a bronze medalist at the 2000 Games, had been the only Olympian to publicly allege abuse by Nassar.

In the past, Nassar and his attorneys have defended the intra-vaginal and intra-rectal procedures as accepted medical practice.

ESPN's John Barr contributed to this report.