Efforts to investigate and punish those responsible for the mistreatment of detainees in Iraq are hampering current military intelligence-gathering operations, prompting extra caution by interrogators and tipping off detainees to U.S. methods, according to senior Army intelligence officers.

Former defense secretary James R. Schlesinger, who led a panel that reported Tuesday on the detainee abuse, was the first to warn this past week of what he called "a chilling effect" on interrogation operations. Since then, several high-ranking military officers in Washington have spoken of the concern among commanders in the field about the trend.

"Have I had people say that to me, as I've done my investigations in Iraq and also in Afghanistan? Yes," said Maj. Gen. George R. Fay, who headed an Army probe of military intelligence soldiers involved in the abuse at the Abu Ghraib prison outside Baghdad. "People are much more reluctant today to be in any way aggressive relative to the collection and the interrogation process."

Another senior Army officer said the widespread publicity about U.S. military intelligence practices has enabled many who end up being taken in for questioning to arrive much better informed about what to expect.

"They know that if the United States captures them, they will get a medical exam," the officer told reporters at a Pentagon briefing Wednesday. "They'll get their teeth fixed. They will get essentially a free physical, and they will be released if they don't talk after a certain amount of time.

"That's the perception of some of the senior officers who work on that. They're getting folks who now know that."

The exposure of U.S. procedures and the throttling back of interrogation practices have come at a time when intelligence analysts are under considerable pressure to produce information about insurgent groups in Iraq and terrorist networks around the world.

"It is essential in the war on terror that we have adequate intelligence and that we have effective interrogation," Schlesinger said.

But the chilling effect has meant reductions and delays in intelligence collection, he added.

The Pentagon has not been alone in feeling this chill. Other government officials recently reported that the CIA has suspended the use of such extraordinary interrogation techniques as feigned suffocation and the refusal of pain medication for injuries -- tactics that had been approved by the White House but are now under review by administration lawyers.

The suspension is related to a White House decision two months ago to review and rewrite sections of an August 2002 Justice Department opinion on interrogations that said torture might be justified in some cases.

Pentagon lawyers have also been reassessing the rules that apply to detainee operations and military interrogations. But Fay, in an interview Thursday with Washington Post editors and reporters, said existing Army doctrine and guidelines provide sufficient "tools" for interrogators to do their work.

Interrogations of captured al Qaeda members in 2002 and 2003 have been credited by U.S. authorities with yielding valuable information about the terrorist network -- its structure, financing, training and planned attacks.

The extent to which this kind of information flow has been curtailed by the fallout from the prison abuse scandal could not be determined.

Military officials were reluctant to provide specific examples of the chilling effect and appeared uncertain even about what gauge to use.

"It's a very difficult thing to measure," Fay said.

In its report, the Schlesinger panel concluded that more work is needed to bring the handling of detainees and military interrogation practices back into line with international law and historical U.S. standards. But the panel also noted that the intelligence challenge confronting U.S. forces has shifted dramatically in the move from the Cold War to the war on terrorism.

"The intelligence problem then was primarily one of monitoring known military sites, troops locations and equipment concentrations," the report said. "The problem today, however, is discovering new information on widely dispersed terrorist and insurgent networks."

As documented in the report, the Pentagon has found itself poorly prepared to deal with this problem, handicapped by a shortage of intelligence analysts, interrogators and interpreters. Further, military intelligence training has for years focused on gaining tactical information -- that is, an enemy's position, strength and movements on a battlefield. By contrast, the need now is for strategic information about a global terrorist threat.

"We have a shortcoming in our system that's emerging out of this" investigation into what went wrong at Abu Ghraib, Gen. Paul J. Kern, who oversaw the Army's probe of military intelligence, told Post staff members Thursday. "That's why you get a lot of questions from these young soldiers: How do I do this? Where do I get all this information?"