The commander of the US marines has called on women whose intimate photos have been shared on marine-run social media sites to come forward, amid a widening scandal which threatens to engulf the entire US military.
Four branches of the military - army, air force, navy and marines - have opened investigations so far.
And General Robert Neller, commandant of the marine corps, appealed to women to come forward and report the problem.
Last week a Facebook page, Marines United, was revealed to be sharing images of naked female marines among its 30,000 users. British royal marines are believed to be among the members of the page.
The whistleblower, a former Marine called Thomas Brennan, has received death threats for lifting the lid on the illicit group. One suggested that Mr Brennan should be waterboarded. He told the Marine Corps Times that users had placed a "bounty" on pictures of his daughter.
"It has been suggested that my wife should be raped as a result of this, and people are openly suggesting I should be killed," he said.
Facebook has shut the page, but other variants have sprung up, with photo sharing on chat forums, Google sites and Dropbox folders.
General Neller said fewer than 10 women had come forward so far.
"I'm going to ask them to trust us - and I understand why that might be a bit of a reach for them right now," said General Neller.
"The only way that there is going to be accountability in this is if somebody comes forward and tells us what happened to them.
“And women, they did their thing, and I don't know what else they got to do to, like, say 'Yeah, OK, good to go.'"
One of the women who was caught up in the scandal, Marine Lance Cpl. Marisa Woytek, told The Washington Post that photos were taken from her Instagram account and posted to Marines United multiple times in the past six months, without her consent.
“Even if I could, I’m never re-enlisting,” she said.
“Being sexually harassed online ruined the Marine Corps for me, and the experience.”
She said she was alerted to the photos by others on social media and were shown the comments that accompanied them – many of which included allusions to sexual assault and rape.
The Naval Criminal Investigative Service has opened an inquiry into the matter, and senior politicians on Capitol Hill have denounced the activity.
Jim Mattis, the defence secretary, said in a statement on Friday that personnel involved in any alleged sharing of nude photos of female colleagues were guilty of "egregious violations of the fundamental values."
The US Code of Military Justice explicitly outlaws distribution of sexually explicit photos of others without their consent as an offense punishable by court-martial.
The Senate Armed Services Committee will hold a hearing on the matter on Tuesday at which General Neller will testify.
"I was going to go to Norway this weekend and see a bunch of Marines above the Arctic Circle. Instead, I'm going to be up on Capitol Hill," he said.
The marines has been long seen as one of the toughest branches of the military for women, and one of the most resistant to allowing women into its ranks.
In January the first three female infantry marines joined their unit at Camp Lejeune, North Carolina.
In March 2016, Ashton Carter, the then defence secretary, approved the marine corps’ plan to allow women to join military occupational specialties that had been restricted to men only. Mr Carter had refused an earlier request by the corps to keep women out of combat jobs, after the service’s gender integration study found that mixed-gender teams did not perform as well as all-male teams and that female marines were more likely to get injured.