The collapse of Saddam Hussein's regime has created some snags in one of the U.S. military's top priorities in Iraq: rescuing American POWs.

Senior defense officials told Fox News they are increasingly concerned about the whereabouts and well-being of the seven U.S. soldiers taken prisoner because the break-down of the regime means "there is no one left to talk to about their whereabouts or their health."

With so many Iraqi troops killed and communications cut off, it's more difficult to find Iraqis who know where the POWs are. The search of a Baghdad military prison where Americans were held as prisoners during the 1991 Persian Gulf War found bloody American uniforms, but not the soldiers who had worn them.

Pentagon officials say American forces are keeping an ear on the remaining Iraqi communications, questioning Iraqi POWs and seeking help from civilians to find and free the U.S. troops.

The rampant looting in Iraqi cities that have fallen out of regime control is also contributing to the POW problem, U.S. officials told Fox News.

They say the looting of "commercial buildings is not a problem" in Baghdad or elsewhere, at least not yet. But the looting of key government buildings could be a problem.

It's in government buildings that U.S. intelligence officers are looking for any evidence of weapons of mass destruction, clues to the whereabouts of key leaders, or any information about the POWs.

Looters may "be taking or pillaging paperwork that could divulge vital secrets about weapons of mass destruction, war crimes, other intelligence about regime operations or the whereabouts of American POWs," one official said.

A tip from an Iraqi lawyer led to the rescue last week of Army Pfc. Jessica Lynch from a hospital in the Euphrates River city of Nasiriyah and the recovery of eight bodies of soldiers who had been captured along with Lynch. Recovering after extensive surgery at a hospital in Germany, Lynch will return to the United States on Saturday.

The seven Americans formally listed as POWs in Iraq include five members of Lynch's Army 507 maintenance unit ambushed on March 23 and the two pilots of an Apache helicopter that went down a day later. Shortly after their capture, Iraqi television showed images of the seven being questioned by their captors.

Representatives from the International Committee of the Red Cross, which monitors POW conditions, have not been able to visit the captured Americans.

Pentagon officials said Thursday they believe all seven are still alive and being held by what's left of Saddam's regime. On Wednesday, the Pentagon's top general called on Iraq to treat the prisoners well and let the Red Cross visit them.

Gen. Richard Myers, chairman of the Joint Chiefs of Staff, said he issued the warning "to not let the Iraqi regime off the hook for doing what is the right thing to do."

Many of the 23 Americans held by Iraq during the 1991 war said they were moved often during their captivity.

Many ended up in Baghdad, held either in the basement of what was then Saddam's secret police headquarters or at the prison in the Rashid military complex in southeastern Baghdad.

Defense officials have no reliable intelligence on the POWs whereabouts but told Fox News it now appears clear they were in fact at the Rashid prison at one point.

The officials said the movement of the POWs to this location suggests "some command authority" had the ability to move them from their capture points in southern Iraq to the capital and that the POWs were supervised -- at least for some period of time.

But now that U.S. forces have confirmed the POWs are not at the expansive Rashid prison, they are mystified about where they might have gone.

"We are worried. Very much so," one official said. "With no regime left, we don't know who to deal with."

Asked by Fox News on Friday as to what the fate of the POWs may be, former CIA operations officer Michael Battles said, "I don't now and it really comes down to the humanity of the attackers."

He noted that if the POWs are being held by Saddam loyalists who have nothing to gain by keeping them safe, chances they will be returned safely may be slim. Regardless of the nature of their captives, he said there's no priority more important to U.S. forces than getting the American prisoners back safe and sound.

"I guarantee you that is the top effort of the intelligence community right now," Battles said.

During the first Gulf War, Jeff Zaun was held by Iraq for 47 days after his A-6E Intruder was shot down and spent much of that time at the Rashid prison. The discovery of uniforms by the U.S. Marines who now control the Rashid base is not a reason to give up hope, Zaun said.

"It's not necessarily something sinister," said Zaun, now of Cherry Hill, N.J. "When I got to Rashid the first thing they did was have me remove my flight suit and they gave me the POW pajamas, took away my shoelaces. It was standard."

Other POWs were held at other Iraqi military installations or at a civilian prison in the Baghdad area.

Daniel Stamaris Jr., the crew chief of an Army Black Hawk helicopter shot down on the last day of the 1991 war, was transferred several times during his week in captivity.

Stamaris, whose legs and pelvis were severely fractured in the crash, was held by Republican Guard forces, left for dead in the desert, taken to a hospital in Basra, held in that city's Baath Party headquarters, then taken to Baghdad.

In the Iraqi capital, Stamaris was held in a cell down the hall from another American prisoner and a British captive. They were guarded by Iraqis in military uniforms.

"Military intelligence never did figure out where we were held," said Stamaris, now a civilian worker at the Army helicopter-training base of Fort Rucker, Ala.

U.S. officials say all the Americans held by Iraq 12 years ago were mistreated, including being beaten and threatened. Stamaris, who was threatened, slapped, spit on and paraded through Basra's streets, said he is worried the current POWs may be suffering similar mistreatment.

"They were never held accountable for what they did to us, and I feel that emboldened them to treat any other prisoners just as bad," Stamaris said.

Fox News' Bret Baier, Major Garrett and Kelly Wright and The Associated Press contributed to this report.