Janis Karpinski, the American brigadier general in charge of Abu Ghraib prison during the abuse scandal, has been demoted to colonel, the United States Army has announced.

Three other, more senior generals have been cleared of wrongdoing the Army confirmed. Karpinski is the only general to be disciplined so far and dropping her in rank required th approval of President George W. Bush.

The demotion means that Karpinsiki's career in the military, where officers must rise in rank or leave, is effectively over.

Some in Congress have sharply criticised the Pentagon for failing to hold the more senior officers in Iraq accountable and instead pinning most of the blame on low-ranking soldiers such as Lynndie England who pleaded guilty on Monday to two counts of conspiracy to maltreat prisoners, four counts of maltreating prisoners and one count of committing an indecent. The military judge has rejected the plea agreement she had reached with prosecutors.

The Senate Armed Services Committee has said it intends to hold hearings soon to assess whether senior Defense Department civilian and military leaders were adequately held accountable for Abu Ghraib.

The Army described its investigations as exhaustive, requiring six months of work including sworn-statement interviews with 82 people, including L. Paul Bremer, who was the top civilian authority in Iraq at the time, and General John Abizaid, the commander of American forces in the Middle East.

Among those cleared by the Army was Lieutenant General Ricardo Sanchez, who was the top Army general in Iraq at the time of the prisoner abuses. He has been faulted by some for leadership failures but has never been accused of ordering or sanctioning any abuse of prisoners. The Army said it could not substantiate two allegations against Sanchez: dereliction in the performance of duties pertaining to detention and interrogation operations and improperly communicating interrogation policies. Lieutenant General Sanchez is currently the commander of 5th Corps, headquartered at Heidelberg, Germany.

The generals who were cleared, in addition to Lieutenant General Sanchez, were Major General Walter Wojdakowski, who was Sanchez’s deputy in Iraq at the time, and Sanchez’s intelligence chief, Major General Barbara Fast. Both were accused of dereliction of duty, but the allegations were not substantiated.

Without providing their names, the Army also said that one colonel and two lieutenant colonels linked to detainee abuses in Iraq and Afghanistan were given unspecified administrative punishment. Two other lieutenant colonels were given letters of reprimand.

More than a dozen other lower-ranking officers, whose names were not released, also received various punishments. Three majors were given letters of reprimand and one of the three also was given an unspecified administrative punishment. Three captains were court-martialed, one captain was given an other-than-honorable discharge from the Army, five captains received letters of reprimand, and one was given an unspecified administrative punishment. Two first lieutenants were court-martialed, another received a letter of reprimand and one was given administrative punishment. One second lieutenant was given an other-than-honorable discharge and another was given a letter of reprimand. Two chief warrant officers were court-martialed.

The Army said other cases involving officers linked to detainee abuse are still open, but it did not say how many.

In addition to being demoted, Karpinski received a written reprimand and was formally relieved of command of the 800th Military Police Brigade on April 8, the Army said in a statement.

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