On Tuesday, President Barack Obama described the destruction and loss of lives as “heartbreaking for the nation” and warned of further damage yet to come. “This storm is not yet over,” he added.
Sandy has been described as a hybrid “superstorm” created by an Arctic jet stream wrapping itself around a tropical storm.
The storm has killed at least 117 people since Wednesday, most of them in Haiti as it was charging through the Caribbean.
Deaths were reported in the US states of New York, New Jersey, Pennsylvania, North Carolina, West Virginia, and Maryland.
“This was a devastating storm, maybe the worst that we have ever experienced,” New York City Mayor Michael Bloomberg said at a news conference.
The storm plunged more than 8.2 million people into darkness, more than three million of them in New York and New Jersey. It also forced the shutdown of public transit, schools, airlines, and financial markets in the East Coast’s largest cities.
In New Jersey, officials warned that residents should be prepared to live without electricity for more than a week.