Donna Markham, who was among the first of nearly 100 witnesses expected to speak, claimed her daughter Chelsea saw Nassar for treatment when aged 10 in 1995.

Markham recalled, according to ESPN, how her daughter had told her that Nassar put his "ungloved fingers in me" before explaining how she had then endured a period of self-loathing and drug use before taking her own life aged 23 in 2009. 

Alexis Moore, one of the other witnesses, alleged that she was abused hundreds of times by Nassar during medical appointments.

"You abused your power and my trust in you," Moore reportedly testified. 

"And that is not okay."

Nassar was imprisoned for 60 years in December for three counts relating to having child sex abuse images on his computer.

The sentencing hearing of the 54-year-old, who has already pleaded guilty, began in Michigan yesterday.

Four-time Olympic champion Simone Biles was this week the latest American gymnast to allege she was sexually assaulted by Nassar.

In a statement, the 20-year-old multiple world champion said she was one of "many survivors" of sexual abuse by him.

Fellow Olympic gold medallists Gabby Douglas, Aly Raisman and McKayla Maroney also spoke-out against Nassar.

It has been reported that Moroney may face a $100,000 (£72,000/€83,000) fine if she speaks at Nassar’s sentencing because of a non-disclosure agreement.

Supermodel Chrissy Teigen has already offered to cover the cost.