The sound of generators and chainsaws punctuated the sunrise in New Jersey, where more than a million homes and businesses were without electricity. NJ Transit train service remained suspended while crews cleared about 150 trees and repair signals and overhead wires.

Regional rail service was also suspended in Philadelphia after Isaias raised the Schuylkill River and sent an unsecured construction barge into a bridge. Inspectors were checking for damage. The Interstate 676 highway, which crosses the bridge, was also closed in both directions.

Patrick Foye, chairman of New York City's Metropolitan Transportation Authority, said more than 2,000 trees fell across the system's train and bus network.

"This storm caused severe damage," Foye said Wednesday. "Not since Superstorm Sandy has our system experienced this type of wind."

Two people died when Isaias spun off a tornado that struck a North Carolina mobile home park. Another person died in Pennsylvania when her vehicle was overtaken by water and swept downstream. Three others were killed by falling trees toppled by the storm in Maryland, Connecticut and New York City, and a seventh person died in Delaware when a tree branch fell, authorities said. A woman was found dead inside a New Hampshire house Tuesday evening.

Isaias sustained top winds of up to 105km/h (65mph) more than 18 hours after coming ashore, but it was down to 64km/h (40mph) maximum winds as of early Wednesday, according to the National Hurricane Center.

Isaias toggled between hurricane and tropical storm strength as it churned toward the East Coast. Fuelled by warm ocean waters, the storm got a late burst of strength as a rejuvenated hurricane with top sustained winds of 136 km/h (85 mph) before coming ashore late Monday near Ocean Isle Beach, North Carolina. Its tropical storm status was sustained, but weakened, as it headed north into Canada on Tuesday night.

Before making landfall late on Monday, Isaias killed two people in the Caribbean and battered the Bahamas before brushing past Florida.

Tornadoes were confirmed by the National Weather Service in Virginia, Maryland, Delaware and New Jersey. Power outages also spread as trees fell, with more than 2.7 million customers losing electricity across multiple states as of Wednesday morning, according to PowerOutage.US, which tracks utility reports. New York City’s power utility said it saw more outages from Isaias than from any storm except Superstorm Sandy in 2012.

In Doylestown, Pennsylvania, officials said four children were treated for minor injuries after high winds partially tore the roof off a daycare centre. Also in the Philadelphia suburbs, rescue workers in Delaware County were searching for a young person who fell or jumped into the fast-moving water of a swollen creek, said Timothy Boyce, the county emergency services director.

Some of the worst damage seemed to be east and north of where the hurricane's eye struck land in North Carolina.

"Fortunately, this storm was fast-moving and has already left our state," North Carolina Governor Roy Cooper said Tuesday.