Allegations that US soldiers posted photographs of dead Iraqis on a website in exchange for access to pornography are being investigated by the Pentagon.
The US army could find itself mired in scandal again
An army spokesman said the posting of such pictures by soldiers could be a violation of the military code.
The authenticity of the pictures - some of which are also said to come from Afghanistan - has not been determined.
The US military was hit by scandal in 2004 when photographs of US guards abusing Iraqi prisoners emerged.
'Trade in misery'
The Council on American-Islamic Relations called for an investigation after reports of the pornographic website showing pictures of corpses emerged last week.
"This disgusting trade in human misery is an insult to all those who have served in our nation's military," Arsalan Iftikhar, the group's legal director wrote in a letter to Defence Secretary Donald Rumsfeld.
A spokesman for Mr Rumsfeld said on Tuesday that the Pentagon had recently become aware of the allegations and was looking into them.
"Obviously it is an unacceptable practice," Bryan Whitman said.
Pentagon officials have said the allegations also raise questions about whether the postings could be viewed as violations of the Geneva Conventions, the New York Times reports.
Protocol I of the international conventions says: "The remains of persons who have died for reasons related to occupation or in detention resulting from occupation or hostilities... shall be respected."
The US, however, is not party to this protocol, which was added to the conventions in 1977.
The website on which the controversial images appear was originally set up for users to trade pornographic pictures of their wives and girlfriends.
Interviewed by the Online Journalism Review of the Annenberg School for Communications last week, the owner of the site said he had offered soldiers free access if they could prove they were members of the military.
Chris Wilson said some sent in pictures of Baghdad traffic signs or of aspects of their life abroad, others sent in pictures of corpses and dismembered bodies.
The pictures are often accompanied by commentaries celebrating the killings but the forum also includes a space for discussion about the war and its purpose.
"This is directly from them [the soldiers]. They can take the digital cameras and take a picture and send it to me, and that's the most raw you can get it. I like to see it from their point of view, and I think it's newsworthy," Mr Wilson told the Online Journalism Review.