The US Naval Criminal Investigative Service (NCIS) has launched a probe into the allegations after a report by a US-based non-profit news organisation uncovered a 'secret' Facebook group -- which has several Marines as members -- that posted naked pictures of US service women,

California-based The Center for Investigative Reporting published a report last weekend, saying that naked pictures of the US service women were shared on a private Facebook group called 'Marines United' -- either posted to the site itself or via links to a Google Drive folder.

The report, authored by Thomas Brennan, noted that the Facebook group consists of nearly 30,000 members and some of whom even posted comments on the images.

"The Marine Corps is deeply concerned about allegations regarding the derogatory online comments and sharing of salacious photographs in a closed website. This behaviour destroys morale, erodes trust and degrades the individual," technology website The Verge quoted Captain Ryan E. Alvis of the Office of Marine Corps Communications as saying on Sunday.

The Facebook group, founded in 2015, was open to male members of the US Marine Corps, Navy Corpsmen and the British Royal Marines.

The group had "vast majority of the posted items were pictures of girls posts without permission, revenge porn, creepy stalker-like photos taken of girls in public, talk about rape, racist comments and just straight bullshit," the report said.

The images posted on the group had over 2,500 comments, including those which urged the publishers to upload additional images.

Some explicit images had information that identified more than two dozen female service members by their names, ranks, duty stations, and branches. While some images were reportedly taken illicitly, others appeared to have been stolen from private accounts.
 

The case comes following the recruitment of first female Marines to Infantry roles. The pictures began circulating a month after the placement of those service women.

The investigation is "in support of two individuals affected by postings on the Marines United site", while legal and other resources will be provided to assist other affected individuals, the report said.

At least one Marine, who shot illicit photographs, was discharged from active duty, while "hundreds of Marines" were being investigated.

A veteran who was responsible for first posting a link to the photos on Google Drive was fired from his position as a government contractor.

Following the publication of the report, Brennan, who is a Marine Corps veteran, has received threats.

According to the report: "There's a bounty on pictures of his daughter; it was suggested that his wife should be raped as a result of this and people were openly suggesting he should be killed."

"I am not going to comment specifically about an on-going investigation, but I will say this: For anyone to target one of our Marines, online or otherwise, in an inappropriate manner, is distasteful and shows an absence of respect," General Robert Neller, Commandant of the Marine Corps, said in a statement.

"The success of every Marine, every team, every unit and command throughout our Corps is based on mutual trust and respect. I expect every Marine to demonstrate the highest integrity and loyalty to fellow Marines at all times, on duty, off-duty, and online. I expect Marines to give their all to be the best human beings, teammates and Marines possible," Neller added.