Tropical storm Isaias left at least five people dead as it pounded the US eastern seaboard with driving winds and heavy rain, leaving millions without power, before moving across Canada on Wednesday.

Locals try to rescue their belonging after the overflow of the Magua river caused by heavy rains caused during Isaias storm in the city of Hato Mayor, northwest of Santo Domingo, Dominican Republic, on July 31, 2020 Locals try to rescue their belonging after the overflow of the Magua river caused by heavy rains caused during Isaias storm in the city of Hato Mayor, northwest of Santo Domingo, Dominican Republic, on July 31, 2020 Photo: afp / Erika SANTELICES

Isaias was downgraded to a post-tropical cyclone late Tuesday as as it streaked across the border into south-eastern Canada after wreaking havoc across several US states.

A tornado ripped through a mobile home park in North Carolina killing two people while two more died as trees fell on their cars -- one in New York and one in Maryland.

Forecast path of tropical storm Isaias Forecast path of tropical storm Isaias Photo: AFP / Nicolas RAMALLO

In Delaware, an 83-year-old woman was found dead under a large branch close to her home.

Forecasters warned of heavy rain across Quebec and wind gusts up to 50 miles (80 kilometers) per hour after the storm littered streets with debris and forced the cancellation of scores of flights in the US.

Hurricane Isaias unleashes flooding, topples trees and knocks out power for thousands Hurricane Isaias unleashes flooding, topples trees and knocks out power for thousands of people in Puerto Rico. Photo: CRISTINA ARRIETA/ESN

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, utilities companies reported -- with New Jersey and New York worst hit by the outages.

A man walks under pouring rain during Isaias storm in Santo Domingo, on July 30, 2020 A man walks under pouring rain during Isaias storm in Santo Domingo, on July 30, 2020 Photo: afp / Erika SANTELICES

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

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

Workers set up temporary plastic flood barriers and sandbags known as 'Tiger Dams' in lower Manhattan to protect the area from flooding as tropical storm Isaias approaches New York City on August 3, 2020 Workers set up temporary plastic flood barriers and sandbags known as 'Tiger Dams' in lower Manhattan to protect the area from flooding as tropical storm Isaias approaches New York City on August 3, 2020 Photo: AFP / Angela Weiss

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

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.

Rough seas and winds develop near North Myrtle Beach in South Carolina as Hurricane Isaias approaches US eastern seaboard. The storm is expected to bring life-threatening storm surges to North and South Carolina. Rough seas and winds develop near North Myrtle Beach in South Carolina as Hurricane Isaias approaches US eastern seaboard. The storm is expected to bring life-threatening storm surges to North and South Carolina. Photo: AFPTV / Logan CYRUS

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 to be less heavy than 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.

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

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

The storm is expected to dissipate over north-eastern Canada late Wednesday or early Thursday.

It 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.