Dhaka, Oct. 13 -- Sixteen people missing after a major explosion at a Tennessee munitions factory on Friday are presumed to be dead, according to the sheriff.

Recovery teams had been clinging to hope of finding any of the missing alive, as of Saturday evening "it's safe" to assume they are deceased, said Humphreys County Sheriff Chris Davis.

Authorities had originally feared that 18 people had died, but two people believed present during the blast were actually not at the site and have been located, according to Davis.

It's still unclear what caused the explosion at the explosives plant in Bucksnort, Tennessee - roughly 56 miles (90km) south-west of Nashville.

Video footage taken on Friday showed fires still burning, charred vehicles,...