LOS ANGELES (Reuters) - Two women from the U.S. Marine Corps, one still on active duty, came forward on Wednesday as victims of a clandestine all-male social media network of military personnel and veterans under investigation for sharing nude photos of female colleagues.

The existence of a private Facebook group called “Marines United” and its surreptitious distribution of explicit images of women in the Armed Forces - often with obscene, misogynist commentary - came to light in published reports over the weekend.

Initially uncovered by The War Horse, a nonprofit news site run by Marine veteran Thomas Brennan, the scandal was first reported on Saturday by the California-based Center for Investigative Reporting through its radio-podcast Reveal.

The Naval Criminal Investigative Service has opened an inquiry into the matter and senior lawmakers on Capitol Hill immediately denounced the activity.

The Marines’ top commander, General Robert Neller, weighed in with a videotaped rebuke on Tuesday, calling the disclosures an “embarrassment” to the corps. “I don’t think such behavior is that of true warriors,” he said.

On Wednesday two women identifying themselves as victims appeared with their Los Angeles-based attorney, Gloria Allred, urging others to come forward and calling on Neller to meet with victims in person.

“I can tell you that this exact behavior leads to the normalization of sexual harassment and even sexual violence,” said Erika Butner, 23, who served in the Marines for four years before leaving the service last June.

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Butner said she learned months later that she was among numerous women from all branches of the military whose pictures were posted without permission to a shared digital drive and organized by name, rank and military base. In some cases, contact information was included, she said.

She was accompanied by Marisa Woytek, an active-duty Marine who said in a written statement that while she was “fully clothed and appropriately dressed” in the photos posted of her, those images drew comments suggestive of sexual violence.

Woytek told the New York Times the pictures were taken from her Instagram account without permission, and she was alerted by friends who sent her a screen shot. “I love the Marine Corps,” she said, “but after seeing that, I wouldn’t re-enlist.”

The U.S. Code of Military Justice explicitly outlaws distribution of sexually explicit photos of others without their consent as an offense punishable by court-marital.

The Facebook group in question is reported to have nearly 30,000 followers, mostly active-duty U.S. Marines, Marine Corps veterans and British Royal Marines. CNN reported Wednesday that group members, rather than halting their network once exposed, moved to other pages with more restrictive access.

The photo sharing, involving thousands of images, began weeks after the first Marine infantry unit was assigned women on Jan. 5, Reveal reported.