(Reuters) - The death toll from a devastating blaze in and around the Great Smoky Mountains National Park in Tennessee rose to 11 on Thursday, the highest loss of civilian life from a single U.S. wildfire in 13 years.

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Investigators have determined the so-called Chimney Tops 2 fire, which laid waste to whole neighborhoods in the resort town of Gatlinburg earlier this week, was caused by unspecified human activity, officials said.

Total property losses from the fire have been put at more than 700 structures, with most of the destruction in Gatlinburg, known as the “gateway to the Great Smoky Mountains,” in eastern Tennessee, about 40 miles (64 km) southeast of Knoxville.

A total of 11 people were killed in the fire, up from seven deaths reported Wednesday, according to Dean Flener, a spokesman for the Tennessee Emergency Management Agency.

That made Chimney Tops 2 the nation’s single deadliest wildfire since 2013, when 19 firefighters died near Prescott, Arizona.

It also ranks as the largest civilian death toll from a U.S. wildfire since 15 people, including a firefighter, were killed in Southern California’s Cedar Fire in 2003, according to Jessica Gardetto, a spokeswoman for the National Interagency Fire Center in Boise, Idaho.

None of the Tennessee victims has been publicly identified, but all were presumed to be civilians, officials from the fire command center told Reuters. As many as 45 people have been reported injured.

The blaze erupted on Nov. 23, Thanksgiving eve, in a remote area of rugged terrain dubbed Chimney Tops in the Great Smoky Mountains National Park near Gatlinburg, authorities said.

Fed by drought-parched brush and trees and stoked by fierce winds, the flames spread quickly days later, igniting numerous spot fires and exploding on Monday into an inferno that roared out of the park into surrounding homes and businesses.

“The wildfire was determined to be human-caused and is currently under investigation,” according to a bulletin released on Thursday by fire commanders and the National Park Service. It gave no further details.

Aerial television news footage showed the burned-out, smoking ruins of dozens of homes surrounded by blackened trees in several neighborhoods.

Steady rains on Tuesday night and into Wednesday helped firefighters slow the blaze, but by Thursday morning officials were still reporting no containment around a fire zone that spanned more than 17,000 acres (6,880 hectares).

“The fire is not out; it is just knocked down,” fire operations chief Mark Jamieson said in the bulletin.

Some 14,000 people were forced to flee their homes at the height of the fire, and most of Gatlinburg, a city of nearly 4,000 residents, remained under mandatory evacuation on Thursday.

Evacuation orders were lifted on Wednesday for the nearby town of Pigeon Forge, home of country music star Dolly Parton’s theme park, Dollywood.