New York Mayor Michael Bloomberg on Sunday ordered the evacuation of 375 000 people in low-lying areas threatened by Hurricane Sandy.
"This is a serious and dangerous storm," Bloomberg told a news conference as he ordered the mandatory evacuation ahead of the storm which is expected to start hitting on Monday.
Airlines have cancelled hundreds of flights into airports along the US east coast ahead of the arrival of a major storm, authorities said Sunday.
Air France cancelled all flights into New York and Washington on Monday while US airlines have called off hundreds of domestic flights. New York airports were to stay open on Sunday but the airport authority warned passengers to expect disruptions.
New York authorities ordered the subway, commuter trains and buses to close on Sunday ahead of the arrival of a feared super-storm.
The New York subway and regional buses will stop from 7pm state governor Mario Cuomo announced as he warned that the impending storm was "not something to be taken lightly."
Hurricane Sandy shadowed the east coast of the United States on Sunday, raking the Carolinas with stinging rains and high waves as authorities braced for the potentially devastating "Frankenstorm" days before the US elections.
The looming superstorm played havoc with the US presidential race, with Barack Obama and Mitt Romney both cancelling campaign events and scrambling to rearrange schedules with the November 6 polls just nine days away.
President Barack Obama moved up a campaign trip to Florida Sunday so he could be back in Washington when the storm makes landfall, predicted for early Tuesday somewhere between Virginia and Massachusetts.
At 1200 GMT, the storm was 420 kilometers southeast of Cape Hateras, North Carolina, packing sustained winds of 120 kilometers per hour, the Miami-based National Hurricane Center said.
Sandy earlier claimed at least 66 lives in the Caribbean, most of them in impoverished, quake-ravaged Haiti where 51 people were reported killed.
Though still far out at sea, the storm was already making its presence felt on US territory, spinning off high winds and seas for hundreds of miles around.
Television images from North Carolina's Outerbanks, a chain of low lying barrier islands, showed wild surf and pelting wind-driven rains that offered a foretaste of conditions to come further north.
The National Hurricane Centre (NHC) warned residents to expect "life-threatening storm surge flooding to the Mid-Atlantic coast, including Long Island Sound and New York Harbour."
At the National Weather Service, forecasters warned the storm would "result in significant impacts along coastal North Carolina" beginning late Saturday.
Current projections show the storm making landfall early Tuesday on the coast of Delaware at near hurricane strength, then bending north and inland as it merges with a cold front descending from Canada.
Weather experts say that collision of a rain-laden tropical storm with a cold front is an explosive mix, creating a super-charged weather system bringing floods, high winds and even heavy snow across a swath of eastern states and as far inland as Ohio.
"Nor'easter on steroids"
Anticipating the worst, governors declared states of emergency in Connecticut, Maryland, Massachusetts, New York, New Jersey, Pennsylvania, Virginia, the US capital Washington and a coastal county in North Carolina.
"This is a large storm that is forecasted to impact the Mid-Atlantic and other parts of the East Coast with strong winds, coastal flooding, inland flooding, rain and snow," said Craig Fugate, head of the US Federal Emergency Management Agency.
"Sandy will be more like a large nor'easter on steroids," wrote Alex Sosnowski, a senior meteorologist for Accuweather.com, who said it could lead to billions of dollars in damage.
In Delaware, Governor Jack Markell issued an evacuation order, urging coastal residents and those in flood-prone areas to leave their homes and to stay safe.
"Please take this evacuation order seriously. It will help save lives of both residents and first responders," he said in a message on Twitter.
New Jersey also ordered evacuations for its southern coastline, including Cape May and Atlantic counties and Long Beach Island. The governor also ordered all gambling shut down in beach-side Atlantic City starting at 3pm on Sunday.
Tolls were suspended on the northbound and westbound lanes of the state's major highways to help residents leave more quickly. – Sapa-AFP and Reuters.