WASHINGTON, June 30: About 3.4 million people were without power in the eastern United States on Saturday from powerful thunderstorms that stretched from Indiana to New Jersey accompanied by record heat.

States of emergency were declared in Ohio, Virginia and West Virginia because of overnight storms with hurricane-force winds that knocked down trees and power cables along an 800-kilometre-long stretch. At least eight people were killed. Forecasters predicted more severe thunderstorms partnered with renewed heat over the next two days.

Restoring power in some areas could stretch into next week and utilities in Ohio and Virginia described damage as “catastrophic.”

“It's going to be a while before some folks get power, and with the heat, that's our big concern,” said Bob Spieldenner, a spokesman for the Virginia Department of Emergency Management.

More than 1 million Virginia customers were out of power in the worst outage not linked to a hurricane in the state's history, he said.

Six people were killed in Virginia in storm-related incidents, Spieldenner said.

About 800,000 customers in Maryland were without power, and every county in the state had reported outages, a spokesman for the state's emergency agency said.

In West Virginia, Governor Ray Tomblin declared a statewide emergency. A spokesman for the state's emergency management office said about 672,000 people were without power.

The storms knocked out power across two-thirds of Ohio, and Governor John Kasich declared a statewide state of emergency.

He said that power could take a week to be restored. Ohio utilities AEP Ohio and Duke Energy reported a total of about 710,000 customers were out of power.

In Atlantic County, New Jersey, officials declared a state of emergency and asked residents to stay off roads as they cleared debris and repaired power lines. About 100,000 power customers in the area were without power.—Reuters