Gymnastics star Simone Biles says Larry Nasser sexually abused her

Four-time Olympic gold medalist Simone Biles said Monday that she had been sexually abused by now-imprisoned Michigan sports doctor Larry Nassar.

In a statement posted on Twitter, Biles described Nasser's behavior as "completely unacceptable, disgusting, and abusive, especially coming from someone whom I was TOLD to trust."

"It is not normal to receive any type of treatment from a trusted team physician and refer to it horrifyingly as the 'special treatment.'" Biles wrote.

Biles, six-time Olympic medalist Aly Raisman, 2012 all-around champion Gabby Douglas and two-time Olympic medalist McKayla Maroney are among more than 100 women and girls who say they were abused by Nassar.

In this Nov. 22, 2017 file photo, Dr. Larry Nassar, 54, appears in court for a plea hearing in Lansing, Mich. Nasser, a sports doctor accused of molesting girls while working for USA Gymnastics and Michigan State University pleaded, guilty to multiple charges of sexual assault and will face at least 25 years in prison.(AP Photo/Paul Sancya)

Michigan prosecutors have asked a judge to sentence Larry Nasser to between 40 and 125 years in prison this week.  (Copyright 2017 The Associated Press. All rights reserved.)

Nassar, who spent more than two decades as a physician at USA Gymnastics while also working at Michigan State University, has admitted sexually assaulting gymnasts, possessing child pornography and molesting girls who sought medical treatment. He was sentenced in December to 60 years in federal prison for possessing child pornography and is facing another 40 to 125 years in prison after pleading guilty to assaulting seven girls.

Biles is in the beginning stages of a return to competition, a journey that includes visits to the national team's training center at the Karolyi Ranch north of Houston, where she said the abuse occurred.

"It is impossibly difficult to relive these experiences and it breaks my heart even more to think that as I work towards my dream of competing in Tokyo 2020, I will have to continually return to the same training facility where I was abused," Biles wrote.

USA Gymnastics initially agreed to buy the Karolyi Ranch in the summer of August 2016, following the retirement of longtime national team coordinator Martha Karolyi, but then backed out of the deal. The national team continues to use the facility while options for a replacement are explored.

Biles posted her statement minutes after Raisman tweeted that she would not attend Nasser's sentencing because it would be "too traumatic" for her.

"I am so proud of you," Raisman tweeted in response to Biles' statement. "You are incredible Simone. I stand with you. I am shaking reading your post. I know we will all get through this together."

USA Gymnastics said in a statement it is "heartbroken, sorry and angry" that Biles and other athletes were harmed by Nassar.

"USA Gymnastics' support is unwavering for Simone and all athletes who courageously came forward to share their experiences," the organization said in a release. "We are our athletes' advocates. USA Gymnastics will continue to listen to our athletes and our members in our efforts of creating a culture of empowerment with a relentless focus on athlete safety every single day."

The organization has taken several steps in recent months. President and CEO Steve Penny resigned under pressure last March and was replaced by Kerry Perry, who took over on Dec. 1.

The organization hired Toby Stark, a child welfare advocate, as its director of SafeSport last summer. Part of Stark's mandate is educating members on rules, educational programs and reporting. The federation also adopted over 70 recommendations by Deborah Daniels, a former federal prosecutor who oversaw an extensive independent review.

That's not far enough for some. Raisman has urged the organization to remove chairman of the board Paul Parilla among others. Biles, like Raisman, wants USA Gymnastics to take a deeper look at the conditions that allowed Nassar's behavior to run unchecked for so long.

"We need to know why this was able to take place for so long and to so many of us," Biles said. "We need to make sure something like this never happens again."

Biles won three gold medals in the all-around, vault and floor exercise as well as a bronze on the balance beam at the 2016 Olympics in Rio de Janeiro. Biles and Raisman also helped the U.S. women's team capture its second consecutive team gold medal.

The Associated Press contributed to this report.