Storm Sandy: US counts cost as Sandy recedes

At least 40 people have been killed, millions are without power and transport across the north-eastern US has been severely disrupted as storm Sandy heads north for Canada.

In New York City, 18 people have been killed and the flooded subway remains closed until further notice. More than 18,000 flights were cancelled, though reduced services are to resume in New York and New Jersey. President Barack Obama, who has suspended his election campaign, is due to visit affected areas in New Jersey.

The storm was causing heavy snowfalls over West Virginia on Tuesday afternoon. It was due to turn towards western New York state before moving into Canada on Wednesday.

Though forecast to weaken, it was expected to cause heavy rain and flooding.

Earlier, Sandy killed nearly 70 people as it hit the Caribbean.

At least eight million homes and businesses are without power because of the storm, says the US Department of Energy.

Sandy brought a record storm surge of almost 14ft (4.2m) to central Manhattan, well above the previous record of 10 feet (3m) during Hurricane Donna in 1960, the National Weather Service said.

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

New York's subway system sustained the worst damage in its 108-year history, said Joseph Lhota, head of the Metropolitan Transit Authority (MTA).

Subway tunnels were flooded and electrical equipment will have to be cleaned before the network can re-open.

Mr Bloomberg said there was "no timeline" for when the subway would restart, but he hoped buses could begin running again on Wednesday.

It is likely to be two or three days before power is restored to most of the city, Mr Bloomberg said. John F Kennedy airport and Newark in New Jersey are due to reopen at 07:00 (11:00 GMT) on Wednesday, with a reduced service, though New York's LaGuardia airport will stay shut.

The New York Stock Exchange says it will also re-open after two days' closure, as will the Nasdaq exchange. The last time the stock exchange shut down for two days was in 1888.