FORT IRWIN, CALIFORNIA (Tribune News Service) — With the desert sky turning red above them, the U.S. soldiers unleashed hell. M1A1 Abrams tanks, AH-64 Apache helicopters and M142 High Mobility Rocket Systems converged on targets as more than 100 military leaders, journalists and other visitors watched from nearby bleachers.

This was the opening act of a huge training exercise at the Army's National Training Center in the Mojave Desert.

Hours later, the 2nd Brigade Combat Team, 82nd Airborne Division would provide the main event with more than 600 paratroopers descending on a moonlit sky.

On paper, the exercise known as Operation Dragon Spear was a joint forcible entry exercise demonstrating Army and Air Force capabilities. But it also was an opportunity for the U.S. military to show those capabilities to the world.

"In my mind this is also about deterrence," said then Army Chief of Staff Raymond T. Odierno. "We're making sure everybody understands we have a capability where, if we have to, we can force our way into an area if it's in our nation's best interest."

Odierno hosted the exercise earlier this month at Fort Irwin, California, alongside Gen. Joseph Votel, commander of U.S. Special Operations Command.

Dragon Spear showed the strength of conventional and special operations forces and how each could work together to take on what the military calls a "near peer" threat.

Officials said the training scenario was not based on any one potential enemy, but they acknowledged similarities to the ongoing Russian military intervention in eastern Ukraine.

Leaders have repeatedly called Russia the nation's top threat.

Odierno reiterated that position last week in his last public briefing as chief of staff.

"I believe Russia is the most dangerous," he said. ". They have stated intents that concern me."

Odierno said the Army has been training for the hybrid threat that Russia poses, with both conventional and insurgent capabilities.

He said U.S. forces need to be able to work together. They need to be expeditionary, scalable and tailorable, and able to deploy quickly.

"A true deterrent is one where people are worried that if they do conduct operations, there will be some level of response," Odierno said.

The skills Odierno referred to were on display during Dragon Spear, which featured several Fort Bragg units.

The road to Operation Dragon Spear began roughly a year before the exercise itself, following a conversation between Odierno and Votel.

The fictional history created for the scenario also dates back close to a year and bears a close resemblance to real-world events.

The training focused on a conflict between two fictional countries known as Donovia and Atropia.

In the training scenario, long-standing tensions between the two countries came to a head after provincial elections in northern Atropia resulted in pro-Donovian candidates being ushered into office. The election had widespread claims of election fraud, intimidation and violence against pro-Atropia leaders.

The pro-Donovian governments declared independence, leading to widespread fighting between Atropian forces and a paramilitary group trained by Donovian special forces known as the Bilasuvar Freedom Brigade.

In the months leading up to the scenario timeframe, Donovian military aircraft infringed on Atropian airspace, and Donovian forces conducted large-scale military exercises on the countries' border.

Nine days before the fictional timeline ended in the real-life Dragon Spear training exercise, Donovian forces crossed the northern border of Atropia, spurring the full-scale U.S. intervention.