Rescue workers began evacuating stranded residents from flooded neighbourhoods after Sandy, the most devastating megastorm in decades, hit densely populated US East coast region, even as President Barack Obama warned that the storm was "not yet over".

The storm hit the East coast with fierce force, killing nearly 50 people across seven US states, plunging millions of homes into darkness and leaving the New York Stock Exchange shut for two straight days for the first time since 1888. Many of the victims were killed by falling trees, Fox news said. Describing the crisis triggered by superstorm Sandy as "heartbreaking", Obama warned the storm was "not yet over".

"This storm is not yet over," Obama said during his trip to the headquarters of the American Red Cross in Washington. Obama drove down to the Red Cross office headquarters to review rescue and recovery operation and said the federal government would push hard to provide resources to the States badly hit by Sandy.

According to a White House statement, Obama will travel to New Jersey to have a personal assessment of the devastation and take stock of the situation on the ground. The trail of destruction left by the monster storm prompted President Obama to declare it a "major disaster" in New York and New Jersey.