Updated

Approximately 190 people perished in the terrorist attack on the Pentagon, a senior defense official said Thursday.

The death toll, which includes the passengers aboard the airliner that slammed into the building, was the first official estimate by the Pentagon. The official, who discussed the matter on condition of anonymity, stressed that the figure of 190 was preliminary.

The Army suffered the largest losses, totaling more than 70 people, and the Navy lost more than 40 people, the official said. The Marine Corps and the Air Force believe they suffered no personnel losses.

The Defense Intelligence Agency lost about seven people, the official said. Some private contract workers also were killed.

American Airlines says the hijacked plane was carrying 64 people, including crew, when it barreled into the Pentagon Tuesday.

As of Thursday morning, about 70 bodies had been removed from the buckled section of the Pentagon as search-and-rescue workers toiled around the clock with little hope of finding more survivors.

FBI crews worked side-by-side, looking for evidence and making their way toward the flight-data and voice recorders of the commercial jetliner that was hijacked by terrorists slammed into the Pentagon Tuesday.

"We're making inroads into the impact area foot by foot now," Fairfax County Capt. Jerry Roussillon said Thursday after search and rescue teams worked through the night stabilizing the damaged parts of the building.

The workers were evacuated Thursday morning for about one hour following a telephoned bomb threat, U.S. officials said.

A nonspecific telephone threat about a bomb forced the evacuation of the rescue workers and law enforcement officials, Pentagon and FBI spokesmen said. The call came some time before 6 a.m. EDT.

The FBI received the threat and "to be cautious" pulled out its people and everyone working in the area, a law enforcement official said.

Search-and-rescue workers were shoring up unstable areas around the impact site and were hoping to be able to enter that area later Thursday to search for more remains as well as the airplane's recorders.

The military services said about 150 people -- mostly Army soldiers -- were unaccounted for, along with 64 passengers and crew from the plane. 

Crews began removing victims' remains Wednesday afternoon but there was no word on how many bodies were recovered. By evening, crews had started tearing down unstable parts of the building to continue their search. They hoped to have enough demolition work done by morning to enter the impact area.

Arlington County, Va., Fire Marshal Shawn Kelley said searchers know "the general area within the building where they can find the black box," but couldn't yet get there.

A small American flag planted on the roof spoke to the Pentagon's determination to restore its spirit despite the horrendous breach of its famous walls.

The little flag was replaced late in the day by a huge one. A dozen firefighters held the banner aloft on the roof, in a display timed to coincide with a visit from President Bush. Then they draped it near the stricken section, a bold display of red, white and blue hanging two-thirds of the way down the wall.

Meantime, stories of harrowing, nick-of-time escapes emerged.

Army Specialist Michael Petrovich, 32, threw a computer through a window, then jumped out behind it, officials said. He has second-degree burns.

Army Lt. Col. Marion Ward, 44, jumped from a second floor window after the plane hit, and suffered smoke inhalation and a sprained ankle. Retired Navy Cmdr. Paul Gonzalez, 46, a budget analyst, got out through the hole in the wall just before the area collapsed. He was in serious condition with burns and respiratory distress.

First lady Laura Bush visited the three in a hospital.

Authorities did not rule out finding people in adjacent areas after a wrecking ball could be used to clear unstable debris, but they did not appear confident of that possibility.

Four search and rescue teams each with 70 members were working around the clock looking for survivors, though Pentagon officials acknowledged the prospects of finding anyone alive was extremely remote.

"Anyone who might have survived the initial impact and collapse could not have survived the fire that followed," the department said in a statement.

Washington-area hospitals treated at least 94 people from the Pentagon, with a minimum of 10 in critical condition. Among them was Louise Kurtz, 49, who was starting her second day of work as an Army accountant. She had burns on about 70 percent of her body.

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