WASHINGTON, Aug 25: An internal US Army investigation published on Wednesday said American military intelligence officials were directly involved in the abuse of Iraqi prisoners at Iraq's Abu Ghraib jail.

The report, which implicates 35 military intelligence personnel and civilian contractors in at least 44 instances of abuse, shows a far greater participation by military intelligence than had ever been made public.

The number of alleged abusers in the report is much higher than were shown in the photos that caused an international outcry. The report, by Maj Gen George R. Fay and Lt Gen Anthony R. Jones, found that 27 of the accused persons directly participated in torturing the prisoners while eight others did not report abuses they knew about or witnessed.

The investigation also implicates 13 military police, seven of them for committing abuses and six for not reporting the abuses they witnessed. Two US military doctors have also been charged with dereliction of duty for failing to report prison abuse.

The inquiry offers a detailed look into the activities of the 205th Military Intelligence Brigade at Abu Ghraib and mirrors an earlier report on 800th Military Police Brigade, responsible for the prison.

Members of the military police brigade cited in the earlier report had said that some instances of prisoner abuse took place under direct instruction of members of military intelligence, an accusation supported by the Fay report.

The report points out that US military intelligence officials conspired to hide at least eight Iraqis detained by US forces from delegations of the International Committee of the Red Cross.

Hiding prisoners from the Red Cross is considered a serious violation of the Geneva Conventions, governing the conduct of prison authorities holding people arrested from a war zone. Geneva Conventions grant all detainees held by an occupying power the right to confer with visiting officials of the Red Cross.

The report says that the number of "ghost detainees" kept hidden from the ICRC was probably more than eight. In the past, Pentagon officials have acknowledged deliberately hiding some detainees from ICRC officials, to keep them in sustained isolation as a means of breaking their resistance to interrogation and to keep their capture secret.

Defence Secretary Donald H. Rumsfeld has told reporters that one detainee was kept hidden on his instructions, following a request by the CIA. Staff Sgt. Christopher Ward, a member of the 372nd Military Police Company deployed at the Abu Ghraib prison in Baghdad, testified this week at a military trial in North Carolina that he was ordered to hide prisoners during at least three ICRC visits last fall and winter.