U.S. President Barack Obama has told Americans to take "very seriously" the arrival of Hurricane Sandy, as hundreds of thousands of residents were being evacuated from New York City.
Speaking in Washington on October 28, he urged the public to observe the instructions of state and local officials.
"Obviously, all of us across the country are concerned about the potential impact of Hurricane Sandy," Obama said. "This is a serious and big storm, and my first message is to all the people across the eastern seaboard, mid-Atlantic, going north that you need 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."
Earlier, New York mayor Michael Bloomberg issued a mandatory evacuation order for 375,000 people in the city, while Governor Andrew Cuomo said public transport in the mega-city was being suspended.
Sandy was expected to make landfall by October 30 near the mid-Atlantic state of Delaware, where it could collide with two winter weather systems as it moves inland.
Bloomberg said the residents in the sprawling mega-city's low lying coastlines should evacuate immediately.
"I am going to sign an executive order mandating evacuation of zone A areas [designated low-lying and coastline areas of New York]," Bloomberg said. "I am also ordering that all of the city's public schools be closed on Monday. Let me stress that we are ordering this evacuation for the safety of the approximately 375,000 people who live in these areas. If you live in these areas you should leave them this afternoon."
Governor Cuomo earlier said public transport was being suspended, including New York's subway.
"The [Metropolitan Transport Authority, New York's public transport company] will suspend bus, subway, and commuter rail service at 7:00 p.m. this evening," Cuomo said. "That includes the New York City Subway System, bus, and all Metro North and Long Island railroad service."
Cuomo said the collision of Sandy with the other two weather systems would likely amount to a "perfect storm."
"When you look at some of the forecasts, [meteorologists] are suggesting a combination of events, and a combination of weather patterns, which they liken to the perfect storm, which was about a combination of two or three different weather patterns colliding," Cuomo said.
Airlines have canceled thousands of flights into and from airports along the U.S. east coast, including transatlantic flights.
States of emergency were declared in New Jersey, New York, Connecticut, Pennsylvania, Maryland, Virginia, and Washington, D.C. Sandy already has killed more than 40 people in the Caribbean en route to its landfall on the U.S. east coast.
President Obama and Republican presidential candidate Mitt Romney have canceled campaign events and rearranged schedules ahead of the November 6 presidential poll.
Based on reporting by Reuters and AFP