LOUISVILLE, Ky. (WDRB) -- Fort Knox training startled many people in the middle of the night from Oldham to Spencer counties. 

Some residents woke up thinking they were in a war zone. They flooded police with calls about low-flying helicopters early Tuesday morning. 

Olga Almanza wasn't quite sure what was in the sky.  

"I don't know. I think it was some type of a UFO, to be honest," she said. 

WDRB viewers shared dark videos of what they say were up to ten choppers in the sky in the middle of the night.  

It turns out that Fort Knox was doing training over parts of Oldham County and eastern Jefferson County.  The post's Public Affairs Office says there was a unit performing flight operations in that area for the past couple of nights. 

Post spokesman Kyle Hodges said that "as a courtesy, the unit did notify the Oldham County Sheriff's office that they would be conducting the exercise ... The community's concerns have been conveyed to the unit, and it will be adjusting its flight path to better avoid residential areas in the future."

Almanza said there were flashing lights that shined red, orange and white around 1:30 a.m. Tuesday as she was delivering newspapers in Jeffersontown. 

People in Oldham, Spencer and Shelby Counties reported hearing helicopters. Heather Becht thought a chopper was landing in her backyard at 3 a.m.

"It was just super loud, and our windows were rattling," Becht said. "Our pictures were like shaking."

Remarkably, her baby, Benjamin, slept through the whole thing, but many others did not.

Concerned neighbors posted to Facebook reporting low-flying helicopters over Crestwood. Another said "It's been a very bizarre night here in La Grange." 

Becht said a little warning would have been nice. 

"If they had told us, it would have been a little more easy to understand," she said. "Now I feel kind of bad for feeling so frustrated, because they were training in the middle of the night, which they desperately need, I'm sure."

Some WDRB viewers also say they heard weaponry being fired. Fort Knox did not confirm that claim.

The training could last through Thursday. 

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