"We're going to continue to push as hard as we can" to provide resources, said the president who has left the campaigning for the Tuesday's election to surrogates to deal with the situation from the White House.
"No bureaucracy, no red tape," was the message to his administration, he said during an afternoon visit Tuesday to the headquarters of the Red Cross in Washington after signing Major Disaster Declarations for worst hit New York and New Jersey.
The lifeline for millions of New Yorkers spanning 468 stations and over 600 miles of track, pulsing through four of New York City's five boroughs, was expected to remain silent for days and power could be out for a week, authorities warned.
More than 18,000 airline flights have been cancelled and according to one estimate Sandy would cost America $10 billion to $20 billion in economic damages.
"The New York City subway system is 108 years old," Joseph J. Lhota, the chairman of the Metropolitan Transportation Authority, was quoted as saying by the New York Times. "It has never faced a disaster as devastating as what we experienced last night."
Recovery efforts across 15 states and Washington city were starting to take hold Tuesday night, but thousands of people waited in shelters, not knowing whether their homes had survived, CNN said.
Atlantic City, a resort town famed for its beaches, boardwalk and blackjack, became an extension of the ocean as seaweed and flotsam swirled in the knee-deep water covering downtown streets.
While the East Coast was still grappling with the scope of the disaster, federal officials warned that Sandy was an ongoing concern with the potential to inflict more pain on inland states.
"The coastal impacts are certainly less today than they were last night, but the effects are not zero," National Hurricane Centre Director Rick Knabb told reporters in a conference call. "There are still some fairly strong winds out of the south."
The storm was centred about 50 miles east of Pittsburgh and packing 45-mph winds Tuesday evening, bringing flood warnings to Michigan, Ohio and Pennsylvania and blizzard warnings to high elevations in the Appalachian Mountains.