Images of men in the uniforms of sailors, soldiers and airmen also appear on an array of Tumblr sites. The Marine Corps is not the only service affected.

In the case of the sites with gay pornography, military investigators will be tasked with determining whether active-duty troops were involved in conduct that could bring discredit on their service, a potential violation of military law. The broadened investigation to an increasing number of websites underscores the complexity of policing social media sites where sensitive images can be uploaded in an instant for all to see. WASHINGTON - The military scandal involving sharing of sexually explicit images of troops has expanded beyond the private social media site Marines United to a slew of gay pornography web pages with images of men wearing military uniforms engaged in sex acts, USA TODAY has learned. Watch Video: Military nudes scandal expands into gay porn sites