The Army has opened an investigation into a Fort Bragg soldier's allegations that he witnessed and heard about widespread prisoner abuse — including torture and a beating with a baseball bat — while serving at a base in Iraq.

The announcement Friday came as a human rights organization prepared to release a scathing report on three 82nd Airborne Division soldiers' accounts of prisoners being beaten, forced to hold five-gallon jugs of water in their outstretched arms, and denied sleep, food and water.

The abuse, one of the sergeants said, was like a game and a way for soldiers to work out their frustrations. The soldiers said there was a great deal of confusion about what types of treatment were allowed under the Geneva convention, and senior officers provided little guidance.

The report was compiled by Human Rights Watch from interviews with a captain and two sergeants who were stationed at a military base called Mercury near Fallujah. The captain said his complaints were ignored for 17 months, and he was denied a pass to leave his base after planning to meet with Senate staff members, the report said.

Army officials, however, said they began their investigation into the matter as soon as it came to their attention.

Army spokesman Paul Boyce said the soldier, whose name was not released, told superiors about the allegations and was then referred to the Army's Criminal Investigation Command. The investigation began at least two weeks ago, he said.

Boyce said the soldier is allowed to contact or visit Congress members or staff but was stopped from traveling to Washington from Fort Bragg in North Carolina on one instance because he had not requested either administrative leave or a pass to leave the base.

The Human Rights Watch report detailed severe, routine beatings of detainees by the 82nd Airborne Division. One of the sergeants told the group that military intelligence personnel, eager for information, often instructed soldiers to "smoke" detainees — called Persons Under Control or PUCs — during questioning, according to the report. "Smoking" prisoners meant physically abusing them until they lost consciousness.

Frustrated soldiers would often beat the Iraqis as a stress release, the sergeant said.

"In a way it was sport," the sergeant said. "One day (another sergeant) shows up and tells a PUC to grab a pole. He told him to bend over and broke the guy's leg with a mini-Louisville Slugger, a metal bat."

The soldier said anything short of death was acceptable. "As long as no PUCs came up dead, it happened," he said. "We kept it to broken arms and legs."

In the report, Human Rights Watch said the soldiers accounts demonstrate that troops were not given clear guidance on how to treat detainee. The group called for Congress to create a special commission to investigate the issue.

Defense Department spokesman Lt. Col. John Skinner criticized the report as a predictable effort to try to "advance an agenda through the use of distortions and errors in fact."

Skinner said the military has investigated all credible allegations of detainee abuse and "looked at all aspects of detention operations under a microscope."