The Pentagon has confirmed it is checking reports that intelligence personnel may have encouraged the alleged abuse of detainees in Iraq.
Abu Ghraib prison was much feared in Saddam Hussein's era
The statement was made by the chairman of the US Joint Chiefs of Staff General Richard Myers.
A US general whose subordinates were photographed abusing Iraqi prisoners has said the cells in question were controlled by military intelligence.
Janis Karpinski, an army reserve general, said she was "sickened" by the images from the Baghdad jail.
Brig Gen Karpinski remains suspended with several other officers.
She told the New York Times that military intelligence officers had been in and out of the high-security cells "24 hours a day".
Gen Richard Myers said on Sunday that US Army intelligence was looking into allegations that intelligence personnel may have encouraged, or pressurised, soldiers to abuse prisoners to help with interrogations.
He spoke after the New Yorker magazine said it had obtained an internal US Army report documenting "sadistic, blatant, and wanton criminal abuses of Iraqi prisoners", including beatings and sodomy.
The BBC's Nick Childs in Washington says the Pentagon top brass are increasingly being accused of not taking the matter seriously enough.
A number of soldiers now face court martial and a possible prison term over the pictures taken at the notorious Abu Ghraib detention facility in Baghdad and broadcast by CBS television on Thursday.
Brig Gen Karpinski, who was in charge of the prison, was suspended in January, while under investigation.
She told the New York Times she believed military commanders were trying to shift the blame onto her and other reservists - and away from intelligence officers still at work
"We're disposable," she said. "Why would they want the active-duty people to take the blame?"
She did not defend the actions of the reservists who are alleged to have taken part in the abuses, she said.
The general added that CIA employees often took part in the interrogations at the prison complex.
The graphic images published around the globe have sparked outrage in the US, Britain and the Middle East.
US President George W Bush said on Friday he was deeply disgusted by the alleged abuses, but that only a "few people" were to blame.
A British newspaper has also published pictures that it said showed British soldiers apparently urinating on a shackled Iraqi prisoner.
But the BBC later quoted sources close to the regiment as saying aspects of the photographs did not seem authentic.