Slideshow ( 3 images )

WASHINGTON (Reuters) - U.S. Senators investigating sexual abuse in sports said on Tuesday they were concerned about “potential systemic issues” involving abuse after written responses from the U.S. Olympic Committee and USA Gymnastics did not provide significant new details about how they responded to accusations of abuse.

The Senate subcommittee is waiting for responses from the national governing bodies of 53 other Olympic sports, from swimming to figure skating, to help determine the extent of abuse.

The U.S. Senate opened its investigation on Jan. 25 after the first sentencing hearing for Larry Nassar, the former doctor for USA Gymnastics’ national team who has pleaded guilty to molesting female athletes. Nassar was sentenced in January and February in two separate hearings to 40 to 175 years and 40 to 125 years in prison.

Senators Jerry Moran, a Republican, and Richard Blumenthal, a Democrat, said in a joint statement that they wanted to know if officials at the sport’s national governing body and the U.S. Olympic Committee (USOC) could have stopped Nassar’s abuse.

“After our initial review, we remain concerned about potential systemic issues within these institutions and plan to seek additional clarification,” the senators, who oversee the Senate’s Subcommittee on Consumer Protection, said in the statement.

USOC and USA Gymnastics did not reply to requests for comment about the senators’ remarks.

The senators shared copies of the written responses from the U.S. Olympic Committee, USA Gymnastics and Michigan State University, where Nassar was also employed and treated young athletes. The president and the athletic director of Michigan State University have resigned, and the school said last week it would fire a dean who oversaw the college where Nassar worked.

Around 200 women, including Olympic gold medal-winning gymnasts Aly Raisman and Jordyn Wieber, gave searing courtroom statements at the sentencing hearings about Nassar’s abuse, leading to the resignation of the entire board of USA Gymnastics.

An early focus of the senators was a complaint by one gymnast that she was coerced into signing a non-disclosure agreement with USA Gymnastics after she complained about Nassar’s abuse.