WASHINGTON - Retired star gymnasts testified before US congress on Tuesday that they were repeatedly sexually abused by a former USA Gymnastics doctor.

Jamie Dantzscher, a 2000 Olympic bronze medalist, and three-time national champion rhythmic gymnast Jessica Howard recounted their experiences before the senate judiciary committee and called for a bill that requires tougher sex-abuse reporting for Olympic sports.

They told the committee of their abuses by Dr Larry Nassar, who is in jail without bond in Michigan and also faces federal child pornography charges.

"USA Gymnastics failed its most basic responsibility to protect the athletes under its care," Dantzscher said through tears.

Senator Dianne Feinstein of California is co-sponsoring a bill that requires organizations overseeing Olympic sports to immediately report allegations of sex abuse to law-enforcement authorities.

The bill and proposed changes to the Ted Stevens Olympic and Amateur Sports Act come in the aftermath of the sex-abuse scandal that led to the resignation of USA Gymnastics president Steve Penny.

"They failed to take action against coaches, trainers and other adults who abused children," Dantzscher said. "And they allowed Dr Nassar to abuse young women and girls for more than 20 years."

Penny is a co-defendant in a civil lawsuit filed by Dantzscher, who has accused Nassar of sexual abuse.

Dominique Moceanu, a 1996 gold medalist, described a "culture of fear, intimidation and humiliation, established by Bela and Marta Karolyi."

The legendary coaches are named in Dantzscher's civil lawsuit for physical abuse.

US Olympic Committee official Rick Adams and Virginia attorney Eric Olsen also testified. Senator Chuck Grassley of Iowa, the committee chairman, criticized USA Gymnastics for declining to testify.

USA Gymnastics said in a statement it "cares deeply" about the issues raised in the hearing and supports the bill.

The organization said chairman Paul Parilla or another official did not appear because of pending litigation.

Moceanu, now an advocate, spoke about emotional and verbal abuse during her time with USA Gymnastics. She said there is an "urgent need" to change the culture of the organization.

Feinstein, who has been critical of USA Gymnastics' handling of the sex-abuse scandal, said she met two months ago with former gymnasts who were abused as teenagers and carried the trauma with them as adults.

Dantzscher and Howard said they didn't realize as teenagers that Nassar had abused them.

"Dr Nassar acted as the good guy, supporting me emotionally and promising me relief from the pain," Howard said. "Now I know that in actuality he expertly abused me under the guise of 'treatment'."

Nassar also was the doctor for Michigan State University's gymnastics team.

He's been charged with sexually assaulting young gymnasts in the Lansing area and faces lawsuits from dozens of former athletes. He has denied wrongdoing.

As part of the proposed legislation, governing bodies under the USOC umbrella would be required to report allegations of sexual abuse to law enforcement and train employees on how to handle situations.

The statute of limitations for victims to sue their abusers would be extended.

"Young athletes should not have to fear victimization from coaches, doctors and other officials," Feinstein said after the hearing.

Retired gymnast Jeanette Antolin told the media conference she was sexually abused by her first coach. She praised the proposed legislation, saying "for so long we felt like we had no voice."

Associated Press