Nine firefighters were killed in a fire that began Monday evening in a South Carolina furniture warehouse — the deadliest fire for firefighters since 9/11, according to the National Fire Protection Association.

Fire swept through the Sofa Super Store and warehouse, collapsing its roof and killing the Charleston Fire Department firefighters inside.

The men ranged in age from 27 to 56, and had worked for the department anywhere from 18 months to 30 years.

Two employees in the building were rescued from the blaze, which broke out at about 7 p.m. Monday, according to the Associated Press.

Firefighters, police officers and other rescue workers saluted as the firefighters' bodies were carried from the warehouse during the night.

"Nine brave, heroic, courageous firefighters of the city of Charleston have perished fighting fire in a most courageous and fearless manner, carrying out their duties," Charleston Mayor Joseph P. Riley said at a morning news conference. "To all of their loved ones, our heart goes out to them."

The cause of the fire was under investigation but Riley said arson was not suspected. He said the blaze apparently started in a storage area. He was unsure whether there were sprinklers in the building.

Witnesses said the collapse of the roof threw debris over about two-dozen rescue workers. Onlookers were hit with flying ash.

"It was like a 30-foot tornado of flames," said Mark Hilton, who was struck in his eye.