WASHINGTON, Sept. 27 - The Army has opened an investigation into whether American troops have sent gruesome photographs of Iraqi war dead to an Internet site where the soldiers were given free access to online pornography, Army officials said Tuesday.

Some photographs on the Internet site show people in American military uniforms standing around what appear to be dead bodies. Other photos include graphic images of severed body parts and what appear to be internal organs spilling from bodies onto the ground.

The images are said to come from Afghanistan as well as Iraq. Their authenticity has not been determined.

Paul Boyce, an Army spokesman, said that if soldiers had posted the images, their actions could violate the Uniform Code of Military Justice, which defines conduct unbecoming an officer or enlisted soldier.