Eighteen people are missing after a blast at a military explosives manufacturing facility in Tennessee on Friday.
Humphreys County Sheriff Chris Davis said one person initially believed to be on site had been located at home. Four or five people were taken to a nearby hospital after the enormous explosion that levelled the factory.
There's nothing to describe, it's gone, he said.
The plant in Bucksnort, Tennessee - roughly 56 miles (90km) south west of Nashville - specializes in the development, manufacture, handling and storage of explosives. The cause of the blast remains unclear.
Aerial video from the scene showed charred debris, smouldering vehicles and little remaining of the facility, which is owned by Accurate Energetic Systems.
Sheriff Davis, who was visibly emotional during his first media briefing of the day, declined to say exactly how many people died.
But he emphasized that the plant had been operational when the explosion occurred, and that secondary blasts forced first responders to maintain a safe distance from the site.
During a second briefing, Davis confirmed that 19 people were still unaccounted for. The explosion occurred in a major building, ejecting debris across a half square mile.
This was a massive enough explosion that I can tell you that folks in Waverly felt and heard this explosion, he noted.
Tennessee Governor Bill Lee referred to the incident as a tragic event via social media, with local and federal authorities collaborating on the ongoing response.
At the scene, emergency responders from local and federal agencies, including the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives, have begun securing the area as they work to piece together what happened. A full investigation is set to follow.
