UFO sighting websites lit up this week after several residents in northern lower Michigan phoned 9-1-1 to report suspicious, unexplained lights in the night sky.

But the conspiracy theory didn't live long.

A military official confirmed today that the lights likely were decoy flares used in a large-scale training exercise that they promoted via press release the morning of the 9-1-1 calls.

Colonel Bryan Teff, commander of the Alpena Combat Readiness Training Center, says operation "Northern Strike 2012" is the largest ever air-to-ground training exercise hosted in Michigan.

Ninteen Air National Guard units from seven different states are gathered in northern Michigan for the exercise, which began Monday and will continue through July 20.

"The primary things that we're doing over the two weeks are focused on close air support and training to provide support for ground forces, whether that be in Afghanistan or somewhere else," Teff said.

Troops are flying a variety of aircraft -- A10s, F16s, E52s, air refeuling tankers and Black Hawk Helicopters -- across much of northern lower Michigan, and performing ground exercises in Alpena and Grayling, which explains why residents across the region reported the mysterious lights on Tuesday night.

The Petoskey News reported that CCE Central Dispatch received 9-1-1 calls from Mackinaw City, Cross Village, Indian River and Cheboygan, where one caller reported a "huge line of gold lights going across the sky."

Teff explained that flare decoys, which were used to mimic air-to-ground missiles, are easily visible from the ground. "This is a training practice environment," he said. "There's no real missiles out there, but we have to practice like they're really fighting."

Teff and other officials in Alpena are hosting units from across the nation, along with NATO coalition troops hailing from Latvia and Canada.

"To us, and the state of Michigan, this is a very big deal," he said. "It provides huge value to the country, preparing all of our international guard, air crew and ground forces for any potential conflict."