The Marine Corps hasn't done anything like it in decades.

Ten thousand Marines, sailors and NATO troops have descended on Marine Corps Air-Ground Combat Center Twentynine Palms in California's Mojave Desert for a massive training exercise.

The troops will be pitted against each other in a force-on-force battle as they prepare for a different kind of fight -- one against an enemy with sophisticated equipment and skills.

Most of the Marines participating are from the North Carolina-based 2nd Marine Division, which hasn't conducted a multi-regimental live-maneuver exercise in decades.

The unscripted Marine Air-Ground Task Force Warfighting Exercise, or MWX, will run for days. In a Wednesday release announcing it, Marine officials called it "unlike any exercise held at the Marine Corps Air-Ground Combat Center."

"An exercise of this scale – force-on-force, multi-regiment outfitted with significant information operations and [unmanned-aerial system] assets – hasn't been conducted in the Marine Corps in my lifetime," Maj. Gen. David Furness, 2nd Marine Division's commanding general, said in the release.

It will test Marines to operate against a "thinking enemy," he added. That's something that was on Gen. David Berger's mind since before he became the Marines' top general.

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Last year, Berger told Military.com that the Corps needed to teach Marine leaders "to think on their feet." If they're someday up against a peer adversary, such as Russia or China, they need to be prepared to face off against "that graduate- or varsity-level thinking leader," Berger added.

"I need them figuring out how they can outthink me," he said at the time.

Furness said the Marine Corps wants to see how his division conducts operations against a mock adversary "with capabilities as advanced as our own."

"MWX will be a true test of the Division's ability to deploy and to operate at scale against a peer threat in a command-and-control denied and degraded environment – an environment where a thinking enemy is working hard to subvert all our efforts," Furness added.

Technology will provide "unique challenges across every level" during this exercise, according to the release. That will include drones along with cyber and electronic warfare.

And to see exactly how the Marines fare, they'll be wearing laser equipment that will alert them if they've been "hit." At that point, they're considered a casualty, and the Marine's unit is responsible for medical assistance and transport as soon as possible.

The unique exercise, according to officials, will challenge how Marines make battlefield decisions.

-- Gina Harkins can be reached at gina.harkins@military.com. Follow her on Twitter @ginaaharkins.