Hurricane Sandy is approaching the U.S. east coast, with winds of 140 kilometers per hour, threatening massive flooding and prompting the evacuation of hundreds of thousands of people.
U.S. President Barack Obama has appeared on national television urging people in the storm's projected path to pay close attention to warnings from their local authorities and be prepared to leave their areas quickly, if requested to do so.
"The most important message that I have for the public right now is please listen to what your state and local officials are saying," Obama said. "When they tell you to evacuate you need to evacuate. Do not delay, don't pause, don't question the instructions that are being given because this is a serious storm and it could potentially have fatal consequences if people haven't acted quickly."
The storm is expected to come ashore late on October 29 or early on October 30, most likely in New Jersey.
Floods and power cuts could affect at least 50 million people.
Sandy is expected to combine with two winter weather systems which could cause snowfalls of up to one meter high.
PHOTO GALLERY: Hurricane Sandy's Landfall
Workers place sandbags at Exchange Place in New Jersey.
People stand on the beach watching the heavy surf caused by the approaching Hurricane Sandy, Cape May, New Jersey.
Raymond Souza carries away a ladder after boarding up Tidal Rave's 5 & 10 gift shop on the boardwalk ahead of Hurricane Sandy's landfall in Rehoboth Beach, Delaware.
The Statue of Liberty is seen in the background as tourists from Russia pose for pictures on top of sand bags protecting Battery Park in Lower Manhattan, New York.
U.S. President Barack Obama speaks to the press after a briefing on Hurricane Sandy at the Federal Emergency Management Agency (FEMA) in Washington.
A person walks through a park along the Hudson River across from New York's Lower Manhattan as rain falls in Hoboken, New Jersey.
A woman and child walk through an aisle, emptied in preparation for Hurricane Sandy, in a Wal-Mart store in Riverhead, New York.
A woman takes photographs of waves pushed onto a road by Hurricane Sandy in Southampton, New York.
A New York Police officer guards a closed subway entrance in downtown Manhattan as Hurricane Sandy makes its approach in New York.
Sandbags block the entrance of the New York Stock Exchange in downtown Manhattan as Hurricane Sandy draws near the city.
A woman takes a photo at Beach 98th street on the boardwalk at Rockaway Beach in the Queens borough of New York.
People walk by sand bags in front of a building in Times Square as Hurricane Sandy begins to affect the area in New York City.
A car sits in a flooded street near the ocean ahead of Hurricane Sandy in Atlantic City, New Jersey.
A flooded street between two casinos along the Boardwalk before the arrival of Hurricane Sandy in Atlantic City.
U.S.Coast Guard Station Barnegat Light, New Jersey, and the surrounding area is shown flooded in this handout photo supplied by the U.S. Coast Guard as Hurricane Sandy moves into the area.
Flood waters rush into the Hoboken PATH train station through an elevator shaft in Hoboken, New Jersey.
Water rushes into the Carey Tunnel (previously the Brooklyn Battery Tunnel) in New York.
A Con Edison worker walks through the flood waters on the corner of 33th Street and 1st Street in front of NYU Langone Medical Center in Manhattan.
High surf on the Hudson River near the Statue of Liberty in New York
A car drives through water driven onto a roadway by Hurricane Sandy in Southampton, New York.
The "HMS Bounty," a replica of an 18th-century sailing vessel, is shown submerged in the Atlantic Ocean southeast of Hatteras, North Carolina. At least one crew member died and another, the captain, is still missing.
"HMS Bounty" in a 2003 photo
A state of emergency has been declared from North Carolina to Connecticut.
Public transportation is suspended in New York City and Washington.
The U.S. stock market will remain closed on October 30.
Two of the tunnels connecting Manhattan to New Jersey and the Holland and Battery New York City boroughs were ordered to close due to fears of flooding.
President Obama warned the consequences of the storm could last for several days after the hurricane itself has passed.
"Probably the most significant impact for a lot of people in addition to flooding is going to be getting power back on," he said. "We anticipate that there are going to be a lot of trees down, a lot of water."
Sandy has already killed more than 60 people after sweeping through the Caribbean.
Thousands of domestic and international flights in and out of the eastern United States have been canceled.
With reporting by AP and AFP