Washington, Jan 23 (IANS): The United States Gymnastics Board of Directors executive leadership -- Chairman Paul Parilla, Vice Chairman Jay Binder and Treasurer Bitsy Kelley -- have resigned amid a sex scandal.

US Gymnastics has been under fire since former gymnastics doctor Larry Nassar admitted molesting athletes during medical treatment when he was employed by Michigan State University and USA Gymnastics. Nassar has already been sentenced to 60 years in prison for child pornography crimes, reports Xinhua news agency.

"US Gymnastics thanks Paul Parilla, Jay Binder and Bitsy Kelley for their many years of service to this organization. We support their decisions to resign at this time. We believe this step will allow us to more effectively move forward in implementing change within our organization," US Gymnastics President and CEO Kerry Perry said in a statement.

"As the board identifies its next chair and fills the vacant board positions, we remain focused on working every day to ensure that our culture, policies and actions reflect our commitment to those we serve," he added.

Nassar has pleaded guilty to multiple charges of sexual assault under the guise of medical treatment.

As a court in Lansing, Michigan has been listening to victims testifying abuses before Nassar's sentencing later this week, pressures are also mounting on US Gymnastics.

Some of the victims went further and alleged that the organization sought to buy silence with regard to the abuse by Nassar.

More than 100 victims of the disgraced doctor have reported sexual assaults to police, including several Olympic medallists from the team of American gymnasts.

Many of the victims were teenagers when they were sexually abused by Nassar, with his hands, during medical treatment.

Following the disclosure of the scandal, the former USA Gymnastics president resigned last year and the organization adopted a series of measures in order to prevent future cases of abuse.