New York came to a standstill after this morning's devastating attack on the twin towers of the World Trade Center. By mid-afternoon 600 people had been taken to hospital of whom 150 were critically injured.
Streets in Manhattan were evacuated to allow emergency vehicles get through. Offices and shops were closed. Army Humvees appeared on the streets downtown as National Guard troops were deployed to prevent looting and help the emergency services.
A military jet roared overhead. West Side Highway, the main artery which runs the length of Manhattan was converted for a two mile stretch into an emergency operations centre. At the point where it passed the World Trade Center an overhead walkway had been brought crashing down on top of an ambulance by masses of falling debris, completely blocking the road.
The subway, some of whose lines run beneath the World Trade Center, was closed, and office workers in mid and uptown Manhattan were also sent home early.
The Brooklyn Bridge was shut off as smoke and dust billowed from the burning buildings just a few blocks to the west. All other bridges and tunnels were later closed. The airports at JFK, La Guardia and Newark were shut down, stranding tens of thousands of people trying to leave the city on regular flights.
All hospitals were put on alert to receive casualties. Patients who could walk were sent home so that the thousands of casualties could be treated. Fifty hospitals were taking the wounded and another 120 were called into service in the New York area, said Mayor Rudolph Giuliani.
The mayor almost became a casualty. He was trapped in an adjacent building for a time as one of the two towers collapsed into the street. He escaped through a basement into Park Place.
"Our focus now has to be on saving as many lives as possible," he said at a press conference.
"The number of casualties will be more than anyone of us can bear. We will do everything possible after this barbaric act to make the city secure."
"People should not be frightened."
The US financial markets came to a halt soon after the attacks began at 8.50 a.m. (1.50 p.m. Irish time). The Securities and Exchange Commission said all exchanges closed almost immediately and trading was suspended on the New York Stock Exchange and the Nasdaq Stock Market.
The American Stock Exchange also closed.
"As a safety precaution while the tragic events of today are sorted out, the securities markets have decided not to open for trading today," SEC chairman Harvey Pitt said.
It will be several days before trading resumes as the damage from the collpasing towers was widespread in the streets around.
Wall Street, four blocks south east of the catastrophe was not affected but it was filled for hours with choking acrid smoke. The New York Mercantile Exchange, where energy futures are traded, is in the nearby World Financial Center, which was not directly hit in the plane assault. It lies between the World Trade Center and the Hudson River. Many of the big US investment firms have offices in the downtown financial district.
Hundreds of people rushed to Manhattan hospitals to give blood as every surgeon, doctor, nurse and orderly in the city was recalled for duty.
Many injured people were brought bleeding and covered in dust to St Vincent's Catholic Medical Center in lower Manhattan.
"We are on full alert," said Mark Ackermann, St Vincent's chief corporate officer.
"People are covered with concrete, soot, and other flying objects.
"We are in desperate need of blood." Hundreds of people lined up outside Beth Israel Medical Center in lower Manhattan, and at other centres across the city, to give blood.
Roman Catholic Cardinal Edward Egan went to St Vincent's to comfort the injured.
"I invite all New Yorkers to join in prayer, this is a tragedy that this city can handle," he said.
Many of the 37 victims brought to Bellevue had were in critical condition, and included eight children and a pregnant woman. New York's mayoral primary election today was postponed. Telephone services were overwhelmed as people tried frantically to call their relatives.
Crowds gathered around pay phones near the World Trade Center shortly after the crashes, shouting at those in front to hurry up. Cell phones went off the air for several hours and television cable services were interrupted in the down town Manhattan area for a time.
The toppled twin towers, which symbolised New York's financial prowess, also housed equipment and antennas that transmitted millions of calls each day.
The damage and an unprecedented volume of traffic overwhelmed an already strained communications system. Carriers dependent on the ariels on the Towers included the major communications company Verizon, although it said there was no major disruption of their network. Sprint said the loss of leased landline equipment under one of the buildings was blocking 75,000 long distance calls.
"It's pandemonium," said Keisha Smithwick, who works at WestCom, a company that maintains dedicated phone lines for financial trading.