The two hulking Marine Corps vehicles pulled into a town square in "southern Afghanistan," only to be greeted by a roadside bomb detonating nearby, a rocket-propelled grenade streaking past — blasting debris high into the air — and gunfire raking their position from the second story of a market.

"Allahu akbar! (God is great)," shouted a fighter with a red scarf wrapped about his head as he fired an AK-47 wildly from behind a wrecked green Isuzu.

A Marine and an Afghan soldier went down when another roadside bomb blew up as they approached the Isuzu, sending a black plume into the sky as gunfire was traded back and forth.

It took the remaining Marines and Afghan soldiers just minutes before they cleared the building and emerged, sweat-soaked.

A half-mile away, meanwhile, emerald waves serenely rolled ashore at Marine Corps Training Area Bellows.

The Marines went through some blank-fire practice runs in their new $42 million Infantry Immersion Trainer at Bellows Thursday ahead of its official unveiling today.

It is the third such immersion training facility in the Marine Corps, and nothing else in the U.S. military compares, officials said.

"Avatar" Afghans — some armed, some not — will be projected on interior walls, and Marines have to make a split-second decision to shoot or not shoot.

The three enclaves, spread out in Bellows, look like Afghan villages, right down to a fake red poppy patch outside one courtyard. They are populated by two dozen Afghan national role-players, and the villages have the smells of pigs, sheep and bread shops misted into the air for added realism.

A separate army of contractors and 352 cameras watch every action behind the scenes in an "after action review" room.

"This facility is going to save lives," said Marine gunner James Law, who is with the 3rd Marine Regiment at Kaneohe Bay.

Law said the "No. 1 great thing about this facility is we make all the mistakes here, and your command can come back and nickel-and-dime you on every little thing that you made a mistake on" so when Marines go to combat, hopefully they won’t make the same mistake again.

Hawaii-based Marines, Schofield Barracks soldiers, Hawaii Army National Guard and Reserve soldiers, and troops from around the region are expected to use the realistic training center.

"This facility is going to be used by everyone" in U.S. Pacific Command, Law said.

The immersion trainer built upon a series of "Afghan villages" that had been in place along dusty gravel roads out in Bellows’ jungly overgrowth. The villages were fashioned from shipping containers.

New stucco-covered buildings and walls are reconfigurable. Marines say the mock district centers are highly accurate in scope and scale. Clothes hang on lines in a maze of walled courtyards. The facility now has 55 structures of various sizes.

The market has one shop full of computer monitors. Vendors hawk fruits and vegetables. Music can be heard, and recordings of dog barks and children playing sound like the real thing.

"It definitely gives you the feeling of being in an Afghan village," said Sgt. Scott Whittington. "Those little doors into the shops, people hanging out — it’s like no detail was left out."

In 2007 the Marines opened a similarly themed Infantry Immersion Trainer in a former tomato packing warehouse at Camp Pendleton, Calif., expanding it almost four times in size in 2010.

Originally configured for Iraq, the trainer was later modified to replicate Afghanistan. An Infantry Immersion Trainer also was recently opened at Camp Lejeune in North Carolina.

The Marines didn’t show it Thursday, but the training also gets bloody, with role-players simulating losing limbs in bomb blasts.

Among the role-players at Bellows was Enayat Hissami, 52, who was born in Kabul, Afghanistan, but now is an American citizen. He sometimes play the roles of shopkeeper, translator or enemy fighter.

Marines fire blanks, and rocket-propelled grenade pyrotechnics travel on fixed wires. At some point, nonlethal marking cartridges might be used, officials said.

Cpl. Brian Lovell, 24, who has been to Afghanistan twice with the 2nd Battalion, 3rd Marine Regiment, came out sweating after clearing the second floor of the market in the mock firefight.

"It’s very realistic. it’s a lot like we’re actually in Afghanistan," the Missouri native said. "The buildings — they look a lot like Afghani buildings, and the role-players they have out here look and act exactly as Afghanis do."