New York City is in lockdown as the American east coast braces itself for mega-storm Hurricane Sandy.
Mayor Michael Bloomberg has ordered the evacuation of low-lying areas of the city, which could affect 375,000 people, as well as the closure of all public transport saying the hurricane is a "serious and dangerous storm".
75mph winds are expected to bring a "life-threatening" surge of floodwater right across the Mid-Atlantic coast as well as 10in of rain and 2ft of snow.
A maintenance worker named Vitto attaches plywood to a sidewalk grate at the 2 Broadway building of Lower Manhattan in New York
Bloomberg said in a press conference: "If you don't evacuate, you are not only endangering your life, you are also endangering the lives of the first responders who are going in to rescue you."
President Obama urged Americans "to take this very seriously and follow the instructions of your state and local officials, because they are going to be providing you with the best advice in terms of how to deal with this storm over the coming days" in a separate press conference.
A state of emergency has been declared in Maryland, New York, Pennsylvania, Virginia, Washington DC and a coastal region of North Carolina.
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The subway will close from 7pm (23:00 GMT) on Sunday evening and all buses will cease two hours later. It is only the second time in history that New York's travel network has been shut down, the first being last year when Hurricane Irene struck.
Sandy has already killed 60 people in the Caribbean in the past week including a British man who was blown off the roof of his luxury Bahamas home whilst trying to repair a window shutter.
The sheer scale of Hurricane Sandy is apparent in this NASA satellite photo
Up to 60 million people across 12 states could be affected when it makes landfall as energy companies warn homes could be without power for up to ten days.
Governor Andrew Cuomo said: "A situation like this, you don't want to be overly panicked and overly prepared, but you want to be prudent, you want to do what's necessary."
Many major airlines have announced they will be suspending flights into New York and Washington DC on Monday.
New York mayor Michael Bloomberg speaks about measures the city is taking in preparation for the arrival of Hurricane Sandy
The New York Stock Exchange has no plans to close as yet. Spokesman Rich Adamonis told Reuters news agency: "We continue to monitor the situation and to communicate with government officials, regulators, and markets participants."
New Jersey Governor, Chris Christie, warned people not to be complacent: "I know everyone's saying this isn't going to happen… that the weathermen always get it wrong.
"We have to be prepared for the worst here. I can be as cynical as any of you but when the storm comes, if it's as bad as they're predicting it will be, you're gonna wish you weren't as cynical as you might otherwise have been."
Barack Obama and Mitt Romney have had to amend campaigning plans to take account of the extreme weather. Obama is holding conference calls to plan an emergency response whilst Romney is heading to Ohio instead of a planned trip to Virginia.