Superstorm Sandy has killed at least 29 people and knocked millions out of power across the densely populated US east coast, leaving streets flooded, homes burned and an embankment collapsed.

Sandy, which made landfall in New Jersey early Monday evening, combined with winter storms to become a hybrid storm.

It has impacted 15 states and killed at least 29 people in eight states, according to a CNN report, including 15 in New York and three in New Jersey, two of the hardest-hit areas, overnight.

Other local media have put the death toll up to 33 to 35.

The death toll in New York has risen to 10 and may continue to rise in the largest city of the country, New York city Mayor Michael Bloomberg said Tuesday at a press conference.

"This was a devastating storm, maybe the worst that we have ever experienced," said Bloomberg.

About seven-million to eight-million customers across eight states have been knocked out of power by the superstorm, according to local media reports.

US President Barack Obama on Tuesday declared "a major disaster" in the states of New Jersey and New York, ordering federal aid to supplement state and local recovery from Sandy.

West Virginia Governor Earl Ray Tomblin later announced that his request for a presidential emergency declaration for the state has also been granted.

A huge fire burned about 80 to 100 houses in a flooded community in Queens of New York city on Tuesday, leaving three people injured.

Surging waters driven by the fury of superstorm Sandy breached an embankment in the state of New Jersey on Tuesday, forcing evacuations, local authorities said.

Obama on Tuesday called 13 governors and seven mayors from across the storm affected area, to express his concern for residents who have been, and continue to be, impacted by Sandy and his sadness over the loss of lives, said the White House.

Earlier Monday morning, the US President was updated about superstorm Sandy's track and impact in the White House. The president told his team that the top priority was to "make sure all available resources are being provided to state and local responders as quickly as possible."

Obama also urged Americans to continue to follow the direction and advice of local officials, governors and mayors.

Heading into the final week before Election Day, Obama has had to cancel Wednesday's campaign events in order to focus on the rescue and response efforts, said the White House spokesperson on Tuesday.

Obama will remain in the capital on Wednesday to monitor the response to superstorm Sandy and ensure that "all federal resources continue to be provided to support ongoing state and local recovery efforts," said White House spokesperson Jay Carney in a statement on Tuesday.

That means Obama has to cancel his planned appearance in campaign events in key swing state Ohio on Wednesday.

The incumbent is balancing between his job and the home stretch of his re-election campaign. Due to deteriorating weather conditions, Obama has already canceled planned campaign events for Monday and Tuesday to stay in the capital and closely monitor the impact of the potentially deadly hurricane.

Speaking after a televised statement on Monday noon, Obama told reporters that the campaign was not top priority now and he was not worried about the impact of the storm on his re-election bid.

SAnews.gov.za-Xinhua