Transport chaos and a mood of shock hit Manhattan's streets as realisation of the World Trade Centre attacks filtered through the balmy September morning.

Normally cool New Yorkers were transfixed by the drama. Cars with radios on full blast became mini-news centres as pedestrians caught up with the latest developments. In elevators, on the streets and in the offices, people began to communicate with one another. "Can you believe it?" asked one gentleman on his way to a business meeting.

Obviously still in shock, people are checking in with friends and colleagues, via e-mail and phone (when the phones lines are working). With mobile phones offering patchy service, queues began forming for street side phones.

All traffic downtown came to a standstill, the subways were partially closed, bridges and tunnels connecting the island of Manhattan with the surrounding areas were sealed and airspace was closed. The only thing that appeared to be working was the Staten Island ferry.

Some firms located near Wall Street immediately evacuated their offices but faced problems getting their staff home.

Smoke from the collasped towers was visible in midtown Manhattan and work came to a stop as shocked New Yorkers crowded round television screens.

It is not known when public transport will be reopened, the Federal Aviation Authority is being consulted in regards to the reopening of airports amid multiple reports of aircraft being hijacked.

Travel advisory websites have been shut down, only displaying the message "All facilities are closed due to a state of emergency."

Eye witnesses meanwhile offered dramatic accounts of their experiences. The UK Press Associated quoted James Winter, 30, a British worker living in an apartment close to the World Trade Centre, saying he had been woken by a huge bang at around 8.50am local time.

"I was in bed and there was a huge explosion. The whole building rattled and shook. I ran to the window and there was smoke billowing from the south side of one of the towers. Everyone in my building was panicking and running around."

Joe Trachtenberg told CNN that he was watching the scene from a high point on his building when the second crash took place. "The first tower was smoking hard. Then there was another plane, and before we knew, it just kamikaze went straight into the other tower. There was a mass explosion and windows flying. It was horrible," Mr Trachtenberg said.

Jeff Levine said of the first attack: "It just flew over my head. The plane was flying really low. It was coming from the north, going south. Everybody looked up at it then it went straight into the top of the tower of the WTC.

"It looks like it went through the building. The top of the building is on fire.

Tally Goldstein, an FT reporter at the scene, heard the third explosion when the first tower collapsed. "They were trying to evacuate a six block radius. We thought the danger was over but then suddenly there was a third explosion.

"They were evacuating Trinity church and a school calmly but then the church was enveloped in smoke and people are running like mad. Smoke overtook all of us," she said, from a basement of Bondys Video Store, blocks from the scene."

An eyewitness of the Pentagon attack said she saw what looked like a commercial aircraft flying very low near the Pentagon: "The plane was coming down at less than a 45 degree angle and when then it came down below and then we saw the smoke. The fireball was pretty big."