An explosion at a Tennessee military munitions plant left multiple people dead and missing on Friday, authorities said, as secondary blasts forced rescuers to keep their distance from the burning site.

The blast occurred at Accurate Energetic Systems, according to the Hickman County Sheriff's Office. The company's website says it makes and tests explosives at an eight-building facility that sprawls across wooded hills near Bucksnort, a town about 97 km southwest of Nashville.

“We do have several people at this time unaccounted for. We are trying to be mindful of families and that situation,” Humphreys County Sheriff Chris Davis said at a news conference. "We do have some that are deceased.”

The cause of the explosion was not immediately known. Video from the scene showed flames and heavy smoke rising from a debris field, and residents miles away reported feeling the explosion.

Emergency crews were initially unable to enter the plant because of continuing detonations, Hickman County Advanced EMT David Stewart said by phone. He didn't have any details on whether anyone had been hurt.

Accurate Energetic Systems, based in nearby McEwan, did not immediately respond to a phone message seeking comment Friday morning.

“This is a tragedy for our community,” McEwen Mayor Brad Rachford said in an email. He referred further comment to a county official.

Nashville-based WTVF-TV broadcast images of debris strewn about the site, with damaged vehicles in a parking lot. The news station said it received calls from people in the area who felt a large explosion.

Residents in Lobelville, a 20-minute drive from the scene, said they felt their homes shake and some people captured the loud boom of the explosion on their home cameras.

The blast rattled Gentry Stover from his sleep.

“I thought the house had collapsed with me inside of it,” he said by phone. “I live very close to Accurate and I realised about 30 seconds after I woke up that it had to have been that.”