The Wall Street Journal, citing people familiar with the investigations, reported that the US Justice Department is pursuing multiple criminal investigations into sexual abuse in Olympic sports organisations.

Other probes have been launched into potential financial and business misconduct throughout the US Olympic system. 

The inquiries follow in the wake of the sexual abuse case against former national gymnastics team doctor Larry Nassar.

According to the The Wall Street Journal, federal prosecutors have spoken with potential witnesses about alleged abuse and misconduct in Olympic sports organisations, including USA Gymnastics and USA Taekwondo.

The USOPC has announced that it will introduce a five-year strategic plan as it faces up to the challenges presented by a string of recent sex abuse scandals.

Nassar, 55, was given an effective life sentence by a Michigan court for sexually abusing dozens of young female gymnasts entrusted to his care.

He is also serving a 60-year sentence for a federal child pornography conviction.

New chief executive Sarah Hirshland and chairwoman Susanne Lyons acknowledged the shortcomings of the USOPC at their annual address to the national governing body's Assembly last week.

Meanwhile, the USOPC has released a statement.

"Every instance related to potential or actual abuse of athletes warrants thorough investigation," spokesman Mark Jones said.

"We have cooperated with all Government inquiries and will continue to do so."

One focus of the investigation appears to be on "failures" in the Olympic system to respond to signs of widespread child abuse, the Wall Street Journal added.

It said prosecutors have already received documents from the US Center for SafeSport in response to a grand jury subpoena.

The Center is the organisation formed in 2017 to handle sex-abuse cases in the Olympic world.

The newspaper also reported that USA Gymnastics said in bankruptcy filings that it has been responding to Justice Department subpoenas as recently as April.

In response to the report, senators Jerry Moran and Richard Blumenthal issued a joint statement.

"The US Olympic Committee and its affiliated national governing bodies enabled Larry Nassar by turning a blind eye to criminal conduct and then trying to sweep it under the rug," they said.

"Everyone who allowed abuse to continue must be held responsible for any and all violations of the law."

USA Gymnastics said it "is striving to become an athlete-centric organisation that keeps athlete safety and well-being at the forefront of everything it does".

It added: "USA Gymnastics has cooperated fully with any Governmental investigation and will continue to do so in the future."

In a separate statement, USA Taekwondo said: "While we are limited in what we can say while legal proceedings move forward, we want to state clearly that above all else, our top priority at USA Taekwondo is the safety of our athletes."