UPDATE: People across the Tennessee Valley area reported hearing loud booms on Thursday.

Channel 3 has confirmed that the Bureau of Alcohol, Tobacco, Firearms, and Explosives was demonstrating explosives for the U.S. Attorney's Office.

Previously it was reported that another set of explosions were at the Chickamauga Lock, but the Army Corps of Engineers spokesperson said that was not the case and that all blasting on-site had been finished for about a month.

The ATF says the demonstration that was heard Thursday was so prosecutors and law enforcement know what to do in the event of an explosives-related case.

Michael Knight said, "This is an opportunity that is provided in a safe manner. They are able to ask questions and learn more about the explosive effects, especially when it comes to investigating as well as prosecuting."

Knight says the explosives used were both commercial and military grade.

“These items are not commercially available to the public, but they are out there and sometimes they may be stolen and used in various crimes and so this gave an opportunity to see from the prosecutor's and law enforcement standpoint on the effects of these explosives,” said Knight.

One of those effects was the sound of booms heard across the Tennessee Valley. 

Reports came in from Red Bank, Tennessee all the way to North Georgia.  

The wintry conditions can be credited.

The wind carried the booms due to the leaves being off the trees making sound travel farther than normal.

Knight says the training was just for one day. He doesn't expect any more demonstrations any time soon, but wants to remind everyone if you see or hear something suspicious, say something.

Mick Knight said, “If they have any information and if that information is gathered through social media platforms or through any other means on any type of explosives.  They should contact their local authorities, these type of explosives no matter how small could be devastating."

The ATF promises to send us a schedule of the next time they will be setting off explosions.

Stay with the WRCB app for updates to this story.

PREVIOUS STORY: People across the Scenic City have reported hearing large booms Thursday.

Channel 3 received dozens of messages and calls from concerned viewers.

Chattanooga police said the Bureau of Alcohol, Tobacco, Firearms, and Explosives is doing explosive demos for the U.S. Attorney's Office.

The Army Corps of Engineers spokesman Mark Rankin initially told Channel 3 that the booming noises were coming from the Chickamauga Lock, where construction is underway. Rankin later said it was not them despite the initial report.

Channel 3 will keep you updated as we learn more.