President Barack Obama has signed an emergency declaration for Washington, ordering federal aid to supplement the state response to a deadly mudslide.

The declaration the president signed Monday authorizes the Federal Emergency Management Agency to mobilize equipment and resources to help ease the impact of the emergency.

The scope of the emergency grew Monday to include scores of people who were still unaccounted for as the death toll from the wall of trees, rocks and debris that swept through the rural community of Oso rose above a dozen. The mudslide hit Saturday in the small town about 55 miles northeast of Seattle.