At least 11 people are dead and more than three million residents are without power after violent storms tore across the eastern United States late Friday.

The storms hit the region during a record heat wave, uprooting trees, knocking down power lines and prompting the governors of at least four states – Maryland, Virginia, West Virginia and Ohio – to declare states of emergency.

The emergency declaration typically gives governors the option of activating National Guard troops, and allows them to take other actions to support public safety and the provision of emergency assistance.

Six deaths were reported in Virginia, two in New Jersey, two in Maryland and one in Ohio – most the result of fallen trees.

Widespread power outages spanned the region, with officials saying it could be a week before everyone's electricity is restored.

Many of the outages were centered in the U.S. capital region, where broken trees and branches littered the streets, and some residents were put under mandatory water restrictions.

In the metropolitan Washington, DC area, the Potomac Electric Power Company, says it could be a week before power is restored to some 378,000 customers in the nation's capital, and the suburban Maryland counties of Montgomery and Prince George's.

PEPCO's Courtney Nogas says at the height of the outages Friday night, 443,000 of their customers were without electricity.

Nogas said late Saturday the company has 800 crew members working around the clock to restore service, and they expect several dozen more crews from Florida, Georgia, Missouri and Oklahoma to arrive by Monday to help them restore service.

Temperatures in Washington reached a record 40 degrees Friday, and on Saturday the extreme temperatures prompted officials at the AT&T National golf tournament in Bethesda, Maryland, outside Washington,DC, to suspended play for several hours. The course had already been closed to spectators and volunteers because of storm damage.