NEW YORK -- The area around the World Trade Center looks more like a war zone than the world's financial capital, after yesterday's attacks on the twin towers left Lower Manhattan covered in heavy soot, airplane parts, twisted metal and other grey debris.

Wave after wave of emergency vehicles raced into the area, bringing busloads of medical workers and police officers to attend to victims. Firefighters and others who rushed to the scene immediately after two hijacked planes crashed into the towers retreated briefly when the buildings collapsed, then continued their rescue efforts throughout the day.

The disaster zone looked like a scene from the Second World War Blitz of London. Windows in dozens of office buildings were blown out; streets in the downtown core were strewn with clothes and office supplies. The blue sky clouded over from soot and smoke raining down from the fires in the towers. Colour disappeared as the landscape turned grey and bleak. At times, no sunlight could penetrate the thick black smoke. The air was pierced only by the shouts of emergency staff.

Hundreds of office workers ran screaming from the centre's pedestrian concourse when the first tower collapsed.

"You want to see blood? I'll show you blood," said one distraught woman, lifting the bottom of her dress to reveal bloody shins and bare feet.

"I was here for the first one," she said, referring to the 1993 bombing of the World Trade Center. "I'm not doing this again."

"It was holy hell," said a man in his 50s, blood and soot covering his shirt.

"I've never seen anything like it. I got out just in time."

Hours after the planes hit the buildings, the smell of burning rubber and paint hung heavily in the air. Police cars and other vehicles sat covered in soot and debris, their windows blown out. Fire trucks lay buried under business papers and plaster from the demolished buildings.

Hundreds of onlookers silently videotaped the disaster, watching thick clouds of smoke swarm the downtown courthouses and City Hall. Many crying workers tried to reach their relatives on cellphones, although service was intermittent. Long lines of bloodied office workers formed near payphones.

New Yorkers praised the city's rescue workers for their fearless response to the tragedy. "I'm on vacation from the fire department," said one firefighter covered in soot. "This is supposed to be my day off. But my job is saving lives."

Many rescue workers were lost in the disaster. The vice-president of the city firefighters' union, Mike Carter, estimated that 200 of the first 400 firefighters on the scene died.

"We have entire companies that are just missing," he said. "We're going to have to bury a lot of people." The city's police department refused to say exactly how many officers were killed, but at least 75 were believed to have died during rescue efforts.

As night fell, reinforcements arrived on the scene, bringing heavy machinery to lift away debris and pull survivors out of the rubble.

Mayor Rudolph Giuliani tried to assure people that the city will survive the attacks.

"New York is still here. We've undergone tremendous losses and we're going to grieve for them, but New York is here and it's going to be here forever," he said.

Outside St. Vincent's Hospital, the closest trauma centre to the disaster site, people milled around hoping for information about friends and relatives.

As hundreds of people looked on with video cameras and issued reports to friends via cellphones, wave after wave of ambulances arrived at the hospital.

By 3 p.m., the hospital had admitted more than 250 of the most critically injured victims, with hundreds of other victims sent to hospitals in New Jersey and Connecticut.

The World Trade Center was a popular draw for thousands of tourists every day. Sherry Ferguson and Rob Redhead came into the city from Toronto on Monday and planned to visit the centre yesterday morning, but they got a late start to their day after drinking late into the previous night. They were just heading out the door when a friend called with the news.

"I can't believe it. We've just been walking around in a daze," Ms. Ferguson said near the site.

"We're both glad we drank too much last night. Otherwise there's the very real possibility that we could have been in the middle of that," Mr. Redhead said.

A few blocks north of the disaster zone, architect Thomas Brown sat in disbelief outside his apartment, watching the fires from the scene still burning in the late afternoon.

"It was the loudest sound I've ever heard," he said, recalling the first plane colliding with the tower. "The World Trade Center is such a focal point, it's how you place yourself. It's always there. I can't believe something so massive could be destroyed like that," he said, shaking his head.

"Every New Yorker knows someone who works there."