Image copyright AFP Image caption Nearly 160 women have accused Nassar of sexual abuse

The entire USA Gymnastics (USAG) board has said it will comply with a US Olympic Committee's (USOC) ultimatum to resign over an abuse scandal.

The USOC earlier said the 18-member board must step down by 31 January or lose status as a sports governing body.

The USOC outlined steps the board must take after ex-USAG doctor Larry Nassar was sentenced to 40 to 175 years for sexually abusing young athletes.

Five directors of the USAG board have already resigned amid the fallout.

Two Michigan State University (MSU) officials have also quit after the school became embroiled in the scandal.

Media playback is unsupported on your device Media caption What it was like to testify against Larry Nassar

Michigan State athletic director Mark Hollis stepped down on Friday following reports that the school knew of the abuse claims but failed to take action.

He said he was "brought to tears" as he listened to Nassar's victims during his sentencing on Tuesday.

"My heart breaks thinking about the incomprehensible pain all of them and their families have experienced," he said in a statement.

Nassar, 54, worked at MSU between 1997 and 2016 and served as national medical co-ordinator for USAG from 1996 to 2014. Nearly 160 women have accused him of sexual abuse.

Media playback is unsupported on your device Media caption From the courtroom: Rachael Denhollander's powerful testimony

USAG has admitted dragging its feet on alerting the authorities when it learned of abuse allegations against Nassar in 2015.

Multiple molestation complaints from young athletes against the physician between 1997 and 2014 were ignored by MSU.

USOC CEO Scott Blackmun wrote in a letter on Thursday that USAG board directors had six days to resign and until 28 February to replace them with an interim panel.

"While the USOC encourages USAG to think and act broadly on reforming its culture, we also believe that reform must start with an entirely new board," Mr Blackmun wrote.

Image copyright Reuters Image caption Critics of Ms Simon say she failed to take action after learning of Nassar abuse claims

He outlined six steps the sports body must take, including:

Replace interim board members in the next 12 months

USAG must co-operate with "an independent investigation" looking into whether the anyone knew of and ignored the abuse allegations against Nassar

The board "must substantially discuss" plans for combating abuse

In a statement on Thursday night, USAG said it "completely embraces the requirements outlined" in the letter and "appreciates the opportunity to work with the USOC to accomplish change".

Michael Burns, the head men's gymnastics coach at the University of Minnesota, became at least the fifth member to resign from USAG's board on Friday.

He confirmed in an email he submitted his resignation letter on Wednesday.

Both USAG and MSU deny there was a cover-up, but some victims have criticised both organisations for not doing enough to prevent the abuse.

Mr Hollis' resignation from the university comes a day after the Michigan State University President Lou Anna Simon quit amid increasing calls for her resignation over the case.

But it was revealed on Friday that Ms Simon can opt to return to a faculty position and take a 12-month leave of absence to conduct research, during which time she would receive her $750,000 (£529,000) salary, according to her contract, which was provided to CNN by Michigan State spokesman Jason Cody.

Olympic gold medallist Aly Raisman, who testified at Nassar's sentencing, slammed USOC in a tweet on Thursday.

Also on Friday, the US House Energy and Commerce Committee announced it would launch an investigation into sexual abuse in organised sports following Nassar's case.

The committee sent letters to USOC, USAG, MSU, USA Swimming, and USA Taekwondo.