By LARRY MARGASAK
The Associated Press

WASHINGTON - The Pentagon said Wednesday no more survivors are expected to be pulled from the tons of rubble and stubborn fires created by the terrorist attack that collapsed a portion of the building.

The lingering smoke prompted the Pentagon to order an evacuation of the building at midday, but the order was almost immediately rescinded.

"It was a false alarm," said Capt. Tim Taylor, a Pentagon spokesman.

Some employees were evacuated because of smoke, but only from one corridor in the Pentagon.

By midmorning, the fire appeared to be out and most of the smoke had cleared, leaving a clear view of the collapsed western wall of the Pentagon. Firefighters using water cannons continued to douse the charred building from either side of the impact area.

Shortly before noon, about 20 FBI agents lined up several hundred yards away from the Pentagon and stretched their arms to form a human chain. They began moving in step across the roadways and grassy areas, carrying brown grocery bags, looking for evidence.

They had done a similar evidence sweep earlier Wednesday, closer to the Pentagon. Both areas were in the line of flight of the plane as it headed for the building.

There was no preliminary estimate of the number of bodies removed from the wreckage.

Ed Plaugher, chief of the Arlington County, Va., Fire Department, which is in charge of the firefighting effort, told a Pentagon news conference that he could offer a ballpark estimate of 100 to 800 deaths. "That's the best we can do," Plaugher said.

The Pentagon said no one could have survived the impact.

"The area of the Pentagon where the aircraft struck and burned sustained catastrophic damage. Anyone who might have survived the initial impact and collapse could not have survived the fire that followed," the Defense Department said in a written statement.

Victoria Clarke, assistant secretary of defense for public affairs, refused to offer a casualty estimate. She said she has no confidence that the number of deaths may be as high as 800.

A senior Army officer said the service, as of early Wednesday, had not accounted for some 70 Army personnel. And a senior Navy officer said the service believed that fewer than 50 people were still missing.

All Air Force personnel were accounted for.

It remains unclear how many Marines, civilian employees of the Defense Department and civilians contractors might have been working in the destroyed segments of the building.

Washington-area hospitals reported at least 94 people had been taken to hospitals from the Pentagon, with a minimum of nine in critical condition. Among them is Louise Kurtz, 49, who was starting her second day of work as an Army accountant and suffered burns to about 70 percent of her body.

"I didn't recognize my wife of 31 years. ... I saw a person who looked like a mummy," said her husband, Michael Kurtz. "I'm mortified and shocked like the rest of the country."

Smoke billowed from the damaged and collapsed areas on the southwestern side of the building, drifting over the northern Virginia skyline.

Teams of a dozen rescuers are equipped with dogs that can differentiate between bodies and live victims; acoustic listening devices that can pick up the faintest sound; and sophisticated cameras.

The Pentagon said listening devices haven't discovered signs of life.

But U.S. officials held out the hope that some people might be found in adjacent areas after a wrecking ball is used to clear unstable rubble.

Around the area of impact along the building's perimeter, where a section of the building collapsed, FBI evidence teams found parts of the fuselage from the Boeing 757. No large pieces apparently survived.

Agents also were looking for the plane's flight-data and cockpit voice recorders.

Air inside the Pentagon was tinged with the scent of an electrical fire. In corridors where workers gathered, water and electricity, phone lines and computers were in full use.

But many corridors ended in blacked-out hallways. Yellow tape and Defense Department policemen warned people away.

The plane smashed a gaping hold across five floors. The aircraft entered the building in the wedge between two corridors, collapsing the outermost ring of the building.

Pentagon officials asked workers in surrounding corridors not to enter their offices because of structural damage.

The chairman of the Joint Chiefs, Army Gen. Henry H. Shelton, was in his office early Wednesday, as was Defense Secretary Donald H. Rumsfeld, officials said.

In the air around the Pentagon, helicopters frequently landed and took off. Military trucks and jeeps went by in convoys. Ambulances and firefighting equipment ringed the area.

Associated Press writer Susanne M. Schafer contributed to this report.