A grim routine set in Friday as superstorm Sandy's US victims struggled to adjust to gas lines, power outages and temporary housing while the death toll from the monster cyclone approached 100.

New York's famed subway lurched back to life with limited service Thursday, offering some relief from the storm-battered city's gridlock, but East Coast residents faced long lines at filling stations and lingering blackouts.

At least 92 people have now been reported dead across the 15 states hit by Monday night's unprecedented storm, including 40 in New York City, while some economists have estimated the disaster will cost up to $50 billion.

More bodies are being found as police and firefighters continue "their lifesaving mission, going block-by-block and door-to-door in the areas devastated by the hurricane," New York Mayor Michael Bloomberg said Thursday.

With about 650,000 people still without power in New York, Bloomberg said the city would start handing out food and water, while National Guard officers and police would go into high-rise buildings to help the elderly.

The Con Edison power company said some New Yorkers would have to wait until November 11 before electricity is restored, and the National Guard was still rescuing people trapped in flooded homes in nearby Hoboken, New Jersey.

The floodwaters receded slowly, leaving scenes of desolation. A yacht, thrown up by the storm, blocked one street near the Hoboken ferry terminal.

The Harman family on Thursday was bailing out the flooded garage they had used as a storage space. Already, they had filled a dumpster with ruined belongings, and a new pile -- children's toys, furniture and household equipment -- gathered on the sidewalk.

Christine Harman, a 43-year-old lawyer, said Hoboken residents were trying to keep their spirits up despite the lack of heat, power and in some apartments, water.

"We're sticking together. In our building we had a party last night. We had a grill on the roof and we cooked the meat that was going to go bad and drank the beer that was going to go off," she told AFP.

New Jersey, which President Barack Obama visited on Wednesday, saw the most widespread destruction, with entire communities along the coast flooded and some 1.8 million people still without power days after the storm.

Obama and Republican White House challenger Mitt Romney resumed full campaigning on Thursday five days out from a nailbiter election, although the tone of their attacks was more muted in the aftermath of the tragedy.

As he launched an ambitious swing through four vital battleground states, Obama took the time to call the governors of worst-hit states New York, New Jersey and Connecticut from aboard Air Force One, the White House said.

Meanwhile, the first subway trains brought some cheer to New York City.

A skeleton service started just before dawn and trains were quickly packed. Train rides were to be free on Thursday and Friday. "It is not comfortable, but it is a huge relief to get moving again," said commuter Dave Stetman.

In a bid to avoid traffic gridlock, Bloomberg said that until Friday cars entering Manhattan must carry at least three people. Police set up checkpoints at bridges and turned back hundreds of vehicles.

Some heartbreaking stories have emerged from the storm.

Two brothers, aged two and four, were swept from their mother's arms in the floods as the family tried to escape the rising seas in the New York City borough of Staten Island.

Glenda Moore's car became stuck in the water, and she was carrying the boys to seek help when they were swept away, the New York Post said. The boys, Connor aged four and Brandon aged two, were later found dead.

Many victims were electrocuted or drowned in flooded basements, while others died from poisoning from the fumes given off by diesel generators put into use since the storm.

The Shell oil company was meanwhile working to clean up a diesel spill off the coast of New York City estimated at up to 300,000 gallons (1.1 million liters), according to the company and the US Coast Guard.

New York police said 28 people had been detained for looting in the Coney Island and Rockaway Beach districts.

Hurricane Sandy brought devastation throughout the Caribbean, hitting Haiti and Cuba especially hard before slamming into the United States and Canada. The overall death toll is now at least 163.

On Thursday the Coast Guard called off the search for the missing captain of a replica of the 18th-century HMS Bounty merchant vessel, which went down in high seas off the Carolinas in the opening hours of the storm's onslaught.