"Super-storm" Sandy has swept across the eastern US coast, bringing heavy rain, high winds and severe flooding. Sandy made landfall in New Jersey, causing a record surge of seawater in New York City, flooding car and subway tunnels and leaving much of lower Manhattan without power. It has been blamed for 10 deaths in several states, Associated Press said. An estimated 50 million people could be affected, with up to one million ordered to evacuate homes. Public transport has been halted in several eastern cities, and thousands of flights have been grounded. Both President Barack Obama and Republican challenger Mitt Romney cancelled campaign appearances little more than a week before the presidential election. The storm made landfall close to Atlantic City in New Jersey at about 20:00 local time (midnight GMT), packing winds of more than 80mph (129km/h). Much of Atlantic City was underwater, and 30,000 residents were evacuated. America's oldest nuclear power plant, Oyster Creek in New Jersey, was put on alert due to rising water, the Nuclear Regulatory Commission said. 'Lower Manhattan covered' Sandy threatens an 800-mile (1,290-km) swathe of the US, from the Atlantic Ocean to the Great Lakes in the Mid-West. It lost its hurricane status late on Monday as it neared the coast and collided with winter weather systems, but was still generating hurricane-strength winds. In New York, some 375,000 residents were ordered out of lower Manhattan and other areas, as the Hudson and East rivers began overflowing. "Lower Manhattan is being covered by seawater," Howard Glaser, director of operations for the New York state government, was quoted as saying. "I am not exaggerating. Seawater is rushing into the Battery Tunnel." Battery Tunnel links Manhattan with Long Island. A spokesman for the city's main utility provider said some 250,000 customers in Manhattan had been left without power. There were reports of an explosion at a Consolidated Edison power station on the east side of Manhattan, but these have not been confirmed. New York Mayor Michael Bloomberg said the storm surge was higher than the highest forecast, but that waters were expected to start receding by midnight local time. Back-up power at New York University hospital had failed and authorities were trying to get people out, he said. Elsewhere in the city, the storm left a construction crane bent double next to a skyscraper and caused the facade off a four-storey building to collapse. Trading on the New York Stock Exchange and Nasdaq will stay suspended for a second day on Tuesday. The United Nations headquarters in New York has also been closed. Associated Press reported 10 deaths in New Jersey, New York, Maryland, Pennsylvania and Connecticut - several due to fallen trees. Forecasters have said Sandy could linger over as many as 12 states for 24-36 hours. President Obama declared emergencies in Massachusetts, Connecticut, Rhode Island, New York, New Jersey and Pennsylvania. In Washington DC, federal government offices were to be closed until Wednesday. Public transport was suspended in the US capital, New York, Baltimore, Philadelphia and Boston. Amtrak has suspended passenger train services across the north-east, while nearly 14,000 flights were cancelled, according to Flightaware.com. Up to 3ft (91cm) of snow is expected to fall on the Appalachian mountains in West Virginia, Virginia and Kentucky. Sandy had earlier killed dozens of people as it passed through the Caribbean, mainly in Haiti.