• Tropical Storm Isaias has so far left four people dead in the US – two in North Carolina, one in New York and one in Maryland.
• Wind gusts up to 80km/h wreaked havoc across eastern states of the US, littering streets with debris and causing flight cancellations.
• About three million houses were without power by early Wednesday morning across several states.

New York – Tropical storm Isaias left four people dead as it pounded the US eastern seaboard with driving winds and heavy rain, leaving millions of households without power on Wednesday.

A tornado ripped through a mobile home park in North Carolina, killing two people, state governor Roy Cooper said on Tuesday, while two more died as trees fell on their cars – one in New York and one in Maryland.

The tropical storm was downgraded late on Tuesday as it streaked into southeastern Canada, where forecasters warned of heavy rain to come.

Earlier, wind gusts up to 80km/h wreaked havoc across eastern states of the US, littering streets with debris and forcing the cancellation of scores of flights.

Video footage from New Jersey showed a roof being torn off a house as residents were told to stay indoors because of a threat of tornadoes.

About three million houses were without power by early Wednesday morning across several states, utilities companies reported – with New Jersey and New York worst hit by the outages.

Isaias quickly moved up the East Coast after slamming into the coast of North Carolina overnight with hurricane strength.

'Don't forget the pandemic is still with us'

"Isaias hit North Carolina head-on," Governor Cooper said, adding that roads were being cleared and electricity restored.

"As clean-up continues, don't forget the pandemic is still with us. So help your neighbour, but do it safely by wearing your mask, keeping your distance and bringing your hand sanitiser."

New York authorities, ever-wary of the devastating damage caused by Superstorm Sandy in 2012, set up temporary flood barriers in Lower Manhattan in case of storm surge.

The orange flexible tubes known as "Tiger Dams" were put up in low-lying areas.

Public transport services were also briefly suspended, including New York's famous Staten Island ferry.

But the rain turned out not to be as heavy as feared.

"The storm has been much more of a wind event than flooding so far, thank God," New York Mayor Bill de Blasio told local news station NY1.

Tornado warnings

At least 78 flights were cancelled at New York's LaGuardia Airport. There were 55 cancellations at JFK.

The fast-moving storm is tracking northeast according to the NHC and is expected to sweep through the northeastern United States and into southern Canada overnight.

Washington, Baltimore and other cities on or near the Atlantic coast experienced heavy rainfall.

"I urge everyone in the storm's path to remain alert and to follow the guidance of your state and local authorities," President Donald Trump said on Tuesday during a White House press conference.

The storm earlier dumped torrential rain on the Bahamas, felling trees and flooding streets, before emergency management officials on Sunday gave the all-clear.

At least one person died in Puerto Rico and the storm also lashed Haiti and the Dominican Republic.