TACOMA, Wash. - Horse owners are grieving after more than a dozen animals died in a fast moving barn fire Thursday night.

Fire officials say 15 horses died in a blaze at the Eckstein Farms boarding stable near Summit, southeast of Tacoma.

The fire broke out at the facility at about 7 p.m. Thursday night. Investigators don't know what caused the fire, but once it sparked, the hay-fueled fire raced through the building.

Flames and dense smoke prevented stable owners and firefighters from rescuing the horses at the barn.

Chief Doug Willis of Central Pierce Fire & Rescue said the horses were all in their stalls.

"We tried to get them out," said Willis. But with flames shooting through the roof, the fire was too dangerous and the battalion chief had to pull back his crew.

Jeremy Eckstein, who works on the farm with his family, said family members couldn't get into the barn because of the dense smoke.

The firefight lasted for an hour, and all the horses inside died.

Fire crews spent the night putting out hot spots because of all the hay and straw inside.

The fire marshall is scheduled to return to the scene Friday to determine what caused the fire.