US President Barack Obama has urged people on America's east coast to take heed of warnings to evacuate before Hurricane Sandy's arrival tonight to avoid "potentially fatal consequences".
Mr Obama, who spoke before Boston joined the list of major east coast cities shutting down transit agencies because of Hurricane Sandy, said the "big and powerful storm" was expected to make landfall on Tuesday evening.
The president said millions of people would be affected and that authorities were working to provide food, water and emergency power. But the clean-up could take some time, he said.
He added: "This is going to be a big storm, it's going to be a difficult storm. The great thing about America is when we go through tough times like this we all pull together, we look out for our friends, we look out for our neighbours and we set aside whatever issues we may have otherwise, to make sure that we respond appropriately and with swiftness. And that is exactly what I anticipate is going to happen here.
"I'm confident that we're ready, but I think the public needs to prepare for the fact that this is going to take a long time for us to clean up. The good news is we will clean up and we will get through this."
Asked if he was concerned about the effect on next week's presidential election, Mr Obama said he was more worried about the impact on families, emergency services, the economy and transportation.
Millions of people stockpiled supplies as the hurricane bore down on the US East Coast, threatening to bring an 11ft (3.4-metre) storm surge to New York.
Two people also remain missing after a crew of 16 on a tall ship - HMS Bounty, which has appeared in films including Pirates Of The Caribbean - were forced to abandon the vessel when it was left stranded around 90 miles (145km) offshore. Helicopters rescued 14 of the crew from life rafts but were still searching for the remaining two.
The replica of the famous vessel was built for the film Mutiny On The Bounty and has appeared in documentaries and films, including Pirates Of The Caribbean: Dead Man's Chest.
Thousands of Britons' travel plans were wrecked as flights were axed, while transport networks in the US were also shut down.