Photo taken on Oct. 29, 2012 shows a flooded street in Atlantic City, New Jersey, the United States. [Xinhua]

Post-Tropical Cyclone Sandy, a former hurricane, had made landfall along the coast of southern New Jersey state as of 8 p.m. EDT on Monday (0100 GMT Tuesday), said the U.S. National Hurricane Center.

As of 8 p.m. EDT (0100 GMT Tuesday), the National Hurricane Center's latest data showed the storm's maxim sustained winds were holding at about 130 kph and the storm was moving northwest at 37 kph.

As of 2 p.m. EDT (1900 GMT), the impacted states in a stretching area from North Carolina up to New Hampshire reported a total of 316,500 power company customers without power, including 105,089 in New York and 87,649 in New Jersey.

But the U.S. media later reported up to 500,000 to 750,000 customers had been knocked out of power on Monday afternoon before the center of the superstorm made its landfall on eastern coast.

"This is going to be a big and powerful storm and all across the Eastern Seaboard I think everybody is taking the appropriate preparations," said President Barack Obama earlier on Monday noon during a televised White House statement.

Obama also said a lot of power outages could be expected in the affected areas and urged people to be prepared for the fact that it would take a long time to clear up after the storm due to its nature of slow moving and wide swath.

Speaking on CNN's State of Union on Sunday, Virginia Governor Bob McDonnell said the state had learned lessons from the last storm which left many local residents without power for days, and already got about 2,000 additional people this time to help with the state's power supply.