Crews from as far away as Canada, Texas and Wyoming raced to remove fallen trees and restore power so customers from Indiana to Delaware would have lights, refrigeration and air-conditioning, as relentless heat gripped much of the eastern United States.

The total without power early Tuesday included about 410,000 in West Virginia, 400,000 in Ohio and 340,000 in Virginia.

Authorities said some customers would not have electricity until the weekend.

"While I want to thank them for their progress, they need to move faster," Washington Mayor Vincent Gray told CNN.

More than 43,000 customers in Washington were without power early Tuesday. Temperatures were forecast to reach 98 degrees Fahrenheit, with a 75 percent chance of thunderstorms in the afternoon.

The 911 emergency phone service in Fairfax County, Va., outside Washington operated at half capacity as Verizon's primary and backup power systems failed after Friday night's storm, leaving much of northern Virginia with no 911 service through the weekend.

Fairfax County is home of the CIA and four other top U.S. intelligence agencies.

AT&T, Sprint, T-Mobile and Verizon said they were trying to get generators to sites that lost power, The Washington Post reported.