Hurricane Irene lashed New York Sunday, shutting down America's largest city and flooding outlying communities after killing at least nine people along the US east coast.

The first hurricane to hit the Big Apple for a generation crashed into Manhattan's skyscrapers overnight, accompanied by lightning, reports of tornados and near horizontal walls of rain.

As Irene approached the New Jersey shore, its wind strength diminished to 75 miles (120 kilometers) an hour, at the threshold of hurricane status. But it still remained a massive storm.

The hurricane made its second landfall near Atlantic City, New Jersey, just before sunrise Sunday and its eye was "nearing New York City," the National Hurricane Center said.

New York City resembled a ghost town after 370,000 people were told to evacuate flood-prone areas, including near Wall Street and at Coney Island, and mass transport was shut down.

Subway trains, buses and the famous Staten Island ferry all closed Saturday, as did all nearby airports, paralyzing the city. Part of the George Washington bridge, connecting Manhattan to New Jersey, was closed.

The immediate fear was that torrential rain, a maximum high tide and more than eight feet (2.8 meters) in wind-driven ocean surge would flood Battery Park in southern Manhattan and on into the narrow streets of the Wall Street district.

But by 1230 GMT the seawalls appeared to be mostly holding, although water lapped over the edges into a park on Manhattan's East River.

There was also severe flooding in beach resorts on Long Island, to the east of the city, and along the famed Jersey shore to to the south.

In Brooklyn, which has a long, low coastline, some streets suffered substantial flooding and the few cars about also had to negotiate a growing number of downed tree branches.

The howling winds set off a number of car alarms and police patrolled the deserted streets and outside shuttered subway stations.

While nearly all shops in the city of more than eight million people were closed, Sam Hamad decided to keep his corner store open. He reported brisk business selling New York bagels, coffee and basic groceries.

"This store is like my own home, so I decided to stay open, even though I had to drive half an hour from where I live to get here," she said.

Claudette Wright, a caregiver at a home for the sick who was heading to work in the storm, was happy to find a shop open.

"I work 16-hour days, so I need my coffee," she said.

In a dramatic press conference late Saturday, Mayor Michael Bloomberg said the time for evacuations was "over."

"At this point, if you haven't evacuated, our suggestion is you stay where you are," he said. "Nature is a lot stronger than the rest of us."

Irene made its first US landfall Saturday at 8:00 am (1200 GMT) at Cape Lookout, North Carolina, near a chain of barrier islands and quickly proved deadly.

At least nine people died Saturday -- in car accidents, by heart attack and by falling trees -- in North Carolina, Virginia and Florida. The youngest victim, an 11-year-old boy, died when a tree crashed through his apartment building in Newport News, Virginia.

The storm then reentered the ocean off the coasts on Virginia and Maryland.

On its passage up the coast, Irene knocked out power supplies for well over a million people, triggered the cancelation of more than 8,000 flights, and forced nearly two million people to evacuate, half of them in New Jersey.

In New York, more than 70,000 people woke without electricity, especially in the outer boroughs of the Bronx, Brooklyn, Queens and Staten Island, power provider Con Edison said.

Officials say Manhattan's skyscrapers are not at risk of serious damage, but warn that power outages might strand residents without light, water or elevators.

The disruption took on an international character after the area's three big airports -- John F. Kennedy International Airport, LaGuardia and Newark -- were ordered to stop all flights at 10:00 pm (0200 GMT).

The website, which tracks airport arrivals and departures, estimated that 8,337 flights would be canceled during the weekend, mainly US domestic trips. It warned that the figure would rise.

President Barack Obama, who cut short his summer vacation, visited the Federal Emergency Management Agency's operations center in Washington on Saturday, where he said the east coast was in for a "long 72 hours."

Obama chaired a meeting at the National Response Coordination Center set up to marshaling federal and local hurricane-relief efforts.

"This is going to be a tough slog getting through this thing," Obama said during a video teleconference including senior federal officials and local government agencies.

Some 65 million people live in the urban corridor from Washington north to Boston, and experts have said the damage could cost anything up to $12 billion to restore.

Hurricanes are rare in the northeastern United States -- the last major hurricane to hit New York was Gloria in 1985.