The hundreds of rescuers searching for survivors underneath the rubble of the collapsed twin towers of the World Trade Center got a much-needed, if ultimately untrue, lift Thursday afternoon when word spread that five firefighters had been pulled out alive.

It turned out, however, that only two firemen were rescued, and that they had been missing for only several hours, having been buried when they fell into an underground pocket Thursday morning.

The dazed but walking firemen were taken to St. Vincent's Hospital in the neighborhood of Greenwich Village, about 1½ miles north of the World Trade Center.

Fox News' Eric Shawn, who was at the rescue scene, stated that one firefighter's name was John Moradito.

The burying, and rescue, of the two men underlined the danger that rescue workers at the site of the world's worst terrorist attack faced as several buildings still standing were judged extremely unstable.

Besides the twin towers, 1 and 2 World Trade Center, two other buildings have collapsed in the area. One of them, the 40-story 7 World Trade Center, otherwise known as the Salamon Brothers building, came down late Tuesday afternoon after having been evacuated.

The top ten floors of 1 Liberty Plaza, across the street from the World Trade Center complex, began buckling about 2 p.m. Thursday and the area around it was cleared.

Other reports Thursday said that two significant bodies had been found. One was in the cockpit area of one of the airplanes, but was not dressed in pilot's clothing, indicating that it may have been one of the hijackers. Another was of a flight attendant — her hands bound together with wire.

Two other firefighters were found dead, locked in an embrace as they were buried underneath the collapsing building.

Meanwhile, Grand Central Station was evacuated at lunchtime due to bomb threats, as were the Conde Nast building (home of the New Yorker, Vogue, Vanity Fair and other magazines) and the Viacom building (which houses MTV) in Times Square.

Midtown Manhattan went back to work Thursday, after two days off. However, a new wave of security concerns shut down most subway lines, meaning that tens of thousands crowded onto overloaded trains.

Despite the encouraging news, people throughout New York and the nation were also trying to come to grips with the inevitable: that thousands of bodies will be pulled from the rubble of the Trade Center and the Pentagon.

New York Mayor Rudolph Giuliani said 4,763 people had been reported missing as of Thursday morning. That number, if added to the deaths from Tuesday's terrorist plane crashes at the Pentagon and in a grassy field southeast of Pittsburgh, would be higher than the death toll from Pearl Harbor and the Titanic combined. A total of 2,390 Americans died at Pearl Harbor nearly 60 years ago, and the sinking of the Titanic claimed 1,500 lives.

Giuliani said 30,000 body bags have been ordered. But he emphasized that the number did not reflect the estimated total of victims; many of the bags will be used for body parts.

President Bush, declaring "I weep and mourn with America," announced he will visit New York on Friday.

"There is a quiet anger in America," Bush said in a telephone conference call with New York Gov. George Pataki and Giuliani.

Weary rescue crews dug through rubble and body parts in the stark glare of spotlights for a second night, desperately hunting for signs of life amid the smoking remains of the landmark Twin Towers. A forecast for thundershowers Thursday night and rain Friday morning threatened to hamper further the search for survivors.

"The volunteers are literally putting their lives at risk," Giuliani said.

Stock markets remained closed for the longest stretch since World War II. Work was slowed by hellish bursts of flame and the collapse of the last standing section of one of the towers taken out Tuesday by terrorists who commandeered two passenger airlines and smashed them into the 110-story skyscrapers.

Early Wednesday, five people were pulled alive from the rubble — including three police officers. But the dead far outweighed the living: the official death toll stood at 94, but thousands of others are presumed dead.

"Let's just say there was a steady stream of body bags coming out all night," said Dr. Todd Wider, a surgeon who was working at a triage center. "That and lots and lots of body parts."

A thick cloud of acrid, white smoke blew through the streets Wednesday after the four-story fragment of the south tower fell. Gusts of flame occasionally jumped up as debris was removed from the smoldering wreckage.

The massive search to uncover the terrorist plot stretched from Miami to Boston to Portland, Maine, and on to Canada and Germany. Up to 50 people were involved in the attack, the Justice Department said, with at least four hijackers trained at U.S. flight schools. Saudi fugitive Osama bin Laden remained a top suspect.

In Washington, President Bush worked with Congress on legislation authorizing military retaliation, and officials revealed that the White House, Air Force One and the president himself were targeted a day earlier.

America's NATO allies bolstered Bush's case for military action, declaring the terrorist attacks an assault on the alliance itself.

At the Pentagon, Defense Department officials said 190 people were feared dead and 70 bodies had been recovered.

In New York, the landscape was a haze of gray dust, splayed girders, paper and boulders of broken concrete. Firefighters armed with cameras and listening devices on long poles searched for survivors. German shepherds and golden retrievers clambered over the debris, sniffing.

A morgue set up in a Brooks Brothers clothing store received remains a limb at a time.

Giuliani was among those who escaped Tuesday's attack uninjured, bolting from a building barely a block from the site when the first of the towers collapsed.

More than 3,000 tons of rubble were taken by boat to a former Staten Island garbage dump, where the FBI and other investigators searched for evidence, hoping to find the planes' black boxes with clues to what happened in the final terrifying minutes before the crashes.

Wall Street and the rest of the nation's financial center remained closed for a third day Thursday, with hopes they may reopen Friday. The shutdown on the New York Stock Exchange was already longer than the two-day closure at the end of World War II; the next longest was for a week after the 1929 market crash.

Insurance industry experts say the attack could become the nation's most expensive man-made disaster ever, with payouts ranging from $5 billion to $25 billion.

North of the immediate disaster area, a much larger swathe of the city, all the way north to 14th St., was closed to all but residents and operators of local businesses. As police and emergency workers demanded that people prove their addresses, this meant that historic Greenwich Village, trendy Tribeca and Soho, the bohemian East Village, the Latino Lower East Side and Chinatown were essentially closed to visitors.

The densely packed bottom tip of Manhattan, an area roughly five square miles, remained off-limits to everyone but emergency workers. Volunteers emerged from the search-and-rescue mission with grisly tales as they cleared away the twisted steel and glass wreckage of the twin towers.

One body was carried out wrapped in an American flag. When workers hung another American flag from a piece of a transmission tower that apparently survived the collapse, "everybody stopped and saluted," said Parish Kelley, a firefighter from Ashburnham, Mass.

Kelley spent the day working in a crater left by the towers' collapse. As he picked through the rubble, he watched as a man's body — a cell phone still clutched in his hand — was carried out.

"We're looking at a pile of rubble 30 to 40 feet high. Where do you start?" said sheriff's Sgt. Mike Goldberg of Hampden County, Mass., accompanying a search-and-rescue dog.

The discovery of a foot and leg and a cockpit seat led to speculation that one of the pilots had been found, Goldberg said.

Survivors held to their spirit, like Marlene Cruz, who sported a neck brace, a leg cast and an unbroken will.

"I wouldn't let a terrorist stop me," she said at Bellevue Hospital. "If the building were still there, I would go back."

For those looking for missing family members, there were unanswered questions. A family grief center set up in a Manhattan armory drew 2,500 family members on Wednesday, said Gov. George Pataki.

Thousands more were expected as the search mission continued.

At St. Vincent's Hospital, where hundreds of victims were treated, a sobbing Annelise Peterson walked in a daze, clutching pictures of her boyfriend and brother.

Peterson asked if anyone had seen either. No one could tell her yes.

Among the missing: at least 202 firefighters and possibly up to 350; 154 workers from the Port Authority; 57 NYPD and Port Authority police officers; 38 members of a Manhattan management company.

Also lost was John P. O'Neill, head of security for the World Trade Center and a former FBI expert on terrorism. O'Neill headed the investigations into the bombing of the USS Cole, along with the bombings of the U.S. embassies in Kenya and Tanzania.

Back at Bellevue, a firefighter almost had to have his leg amputated so he could be freed from the rubble, said Pataki, who visited the hospital to thank medical workers and speak with patients.

The governor asked him why he would risk his life. The unidentified firefighter told him: "What do you expect? I'm a New Yorker."

Fox News' Steve Bromberg, Paul Wagenseil and the Associated Press contributed to this report