The Pentagon has launched an investigation into nude photos of female service members being posted online without their permission.
Fewer than 10 female Marines have so far come forward to make a formal complaint.
General Robert Neller has pleaded with female Marines to "trust us" and reach out to make complaints or seek help.
"I'm going to ask them to trust us. I understand why that might be a bit of a reach for them right now. But I can't fix this. ... The only way there is going to be accountability in this is somebody comes forward and tells us what happened to them."
Former and current female Marines have said their photographs and those of women in other services were shared on social media without their consent.
The other military services say that they are now looking into the matter to see if their service members are involved, but they say so far no other victims have come forward.
Nude photographs of female Marines and other women were shared on the Facebook page "Marines United," and the accompanying posts included obscene and threatening comments.
Speaking to Pentagon reporters, Neller expressed frustration and disgust at the nude-photo sharing.
He said the controversy has an effect on the entire Marine Corps and the investigation must be done carefully.
"We don't want to be in a hurry. We want to make sure we're thorough and we're within the law," he said.
The photo-sharing underscores longer-standing issues surrounding women in the Marine Corps.
In 2015, the Marine Corps was the only military service to ask that women be excluded from competing for certain frontline combat jobs.
Then-Defense Secretary Ash Carter rejected the request, and women are now allowed to seek combat jobs in all the military services.
But there still may be a sense that women aren't accepted by some members of the corps.
Neller has created a task force to look at the scope of the problem and any underlying issues, and to develop plans for any corrective actions, policy changes or additional training that may be needed.
Separately, officials said Defense Secretary Jim Mattis will meet with military and civilian officials in coming days about the reports.
Active-duty Marine Marisa Woytek and former Marine Erika Butner appeared at a news conference in Los Angeles on Wednesday to applaud the investigation.
Butner, 23, who served for four years before leaving the Marines in 2016, said she contacted investigators in January.
The veteran told them there was an online storage drive that contained "indecent photos of women from all military services, organised by name, rank and even where they were stationed."
The women's lawyer, Gloria Allred, said there may be hundreds of such postings and that they prompted pornographic and violent replies, including some recommending that female Marines be raped or shot.