Our police and fire personnel are down there under enormous strain and risk to their lives

George Pataki, Governor of New York

Six survivors are reported to have been dragged from the rubble since two planes smashed into the World Trade Center.

Emergency services have also been receiving phone calls from people trapped inside the remains of the 110-story twin towers.

But wreckage from the buildings is lying two stories deep as rescuers dredge through the dirt and choking dust and everywhere there is the risk from gas leaks.

Rescuers fly the flag for a stricken city

George Pataki, Governor of New York, said: "Our police and fire personnel were heroes on Tuesday and they are still heroes.

"They are down there under enormous strain and risk to their lives."

His comments had particular resonance for the fire service, which fears that at least 200 personnel who went to the rescue after the planes hit the towers, are buried in the rubble.

Thousands of people are believed to have been killed following the collapse of the twin towers and firefighters admit that hopes are fading of finding many more people alive.

Tragic heroes

Rudy Weindler, who spent nearly 12 hours trying to find survivors and only found four, said: "I lost count of all the dead people I saw.

"It is absolutely worse than you could ever imagine."

Firefighter Scott O'Grady, said: "It is unimaginable, devastating, unspeakable carnage.

The search continued through the night

"To say it looks like a war zone and to tell you about bodies lying in the street and blood and steel beams blocking roads would not begin to describe what it's like. It's horrible."

One survivor paid tribute to the tragic police heroes who stepped in before the twin towers toppled.

Bill Hemm said he owes his life to police SWAT team members who prevented evacuees from going into areas of falling debris.

"I know they died," he said.

"They had to have if they were still evacuating people.

That's so sad. I guarantee they saved a bunch of lives."

There are also stories emerging of the unsung heroes.

Brother found

"I started going down the steps," said one survivor.

"There was a woman in a wheelchair. I got her into a strap of the wheelchair and just carried her down the steps, down 68 floors, man.

Grim faces reflect the reality of so many dead

"We got lost on the fifth floor. It was chaos."

Relatives of the few lucky people to escape have spoken of their joy at finding their loved ones.

Jason Beerman rushed toward the twin towers complex as soon as he heard news of the attacks, fearing the worst for older brother, Kenton.

But as 24-year-old Kenton emerged into daylight from the gloom of a smoke-ridden stairwell, one of the first faces he saw was Jason's.

"I don't know how he found me," Kenton said. "He just hugged me and said, `I'm so glad you're alive.'"

Other relatives have been less lucky.

Parag Papki went to five hospitals looking for his brother, Ganesh Ladkat, who worked on the 104th floor of the trade center.

The fire department will recover, but I don't know how

Thomas Von Essen, city fire commissioner,

"They asked me what was he wearing, any body marks, stuff like that," he said.

"Since Tuesday afternoon, I am searching."

In New York, a priest struggled to comfort relatives of one of the many dead firefighters.

"I don't know what to say to them," said the Rev Murray Gerald, who was called to St. Vincent's Hospital in Manhattan.

Thomas Von Essen, a city fire commissioner, was close to tears as he spoke of the loss of firefighters, some with 30 to 40 years of service, reciting some of their names.

"The fire department will recover," he said. "But I don't know how."