Maroney, now aged 21, was part of the United States' women's artistic all-around team that won gold at London 2012.

She also took an individual silver medal in the vault final.

In a statement posted on her Twitter account, Maroney describes in harrowing detail how the abuse allegedly started when she was 13.

"Dr. Nassar told me that I was receiving 'medically necessary treatment that he had been performing on patients for over 30 years,'" the statement read.

"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.

"For me the scariest night of my life happened when I was 15-years-old.

"I had flown all day and night with the team to get to Tokyo.

"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."

Born in California, Maroney also won World Championships team and individual vault gold in Tokyo in 2011.

She defended her vault title two years later in Antwerp.

Maroney commented "#MeToo" with her tweet, a movement designed to encourage women to identify themselves as victims of sexual harassment or assault following the Harvey Weinstein scandal.

A number of women have accused the American film producer of sexual misconduct.

Former members of the US national team made allegations last year of sexual abuse against Nassar.

Jessica Howard, the US national rhythmic gymnastics champion from 1999 to 2001, and Jeanette Antolin, a Pan American Games silver medallist, spoke about the alleged abuse on the CBS 60 Minutes programme in February.

Atlanta 1996 Olympic gold medallist Dominique Moceanu and Sydney 2000 bronze medallist Jamie Dantzscher joined Howard in testifying to a Senate Committee in Washington D.C, with the aim of protecting young athletes from abuse in March.

Dantzscher also filed a lawsuit against Nassar in California last September as "Jane Doe".

According to the Lansing State Journal, Nassar has pleaded guilty to Federal child pornography charges and will be sentenced on December 7.

It is also reported he still faces 33 charges of criminal sexual conduct in Michigan.