BRAD PITT and ANGELINA JOLIE are grappling with their biggest family crisis yet – their four oldest children have turned violent!

The A-list couple’s kids have grown into a brawling mini-mob, sources say, with the main troublemakers being the oldest boys.

In the latest shocker, the concerned superstars yanked their 7-year-old son Pax out of an exclusive private school after he punched a classmate, The ENQUIRER has learned.

"They’re the most famous kids in the world, but it seems as if the older they get, the more violent and belligerent they become," an insider told The ENQUIRER.

"Brad and Angelina are good parents, but their close-in-age instant family has proven difficult to manage – even with nannies and household staff. It’s beyond chaos, and it’s driving Brad and Angelina crazy."

The couple’s multi-ethnic brood includes three adopted children – Cambodian-born Maddox, 9, Vietnamese-born Pax, and Ethiopian-born Zahara, 6. Their biological children are daughter Shiloh, 4, and 2-year-old twins Knox and Vivienne.

And while they represent Brad and Angelina’s dream of raising a rainbow family, the youngsters often display wild behavior, sources say.

"The Jolie-Pitt household has almost become a war zone, with kids screaming, punching and scratching each other," the insider divulged.

"There are fights between Maddox and Pax, while Zahara and Shiloh regularly throw temper tantrums and violently throw things when they don’t get their way.

"The girls have been involved in fighting and shoving matches with each other and with the boys."

Worst of all, the sibling rivalry between Maddox and Pax has escalated to the point where Brad has had to step in to shield the twins, said the source.

"Maddox likes to fight for fun," the source said.

"His wrestling matches and war games with Pax are completely out of control. They throw everything from food to sharp-edged toys at each other, and their brawls often lead to scraped arms and knees, cut faces or bloody noses.

"Brad tries to keep Knox and Vivienne protected and out of the fray."

While the knives may belong to Maddox, his younger brother’s violent behavior has attracted attention at his $15,000-a-year school, the tony Le Lycee Francais in Los Angeles, according to another source.

"Not only does Pax have knock-down, drag-out fights with Maddox, some people at the school think Pax has anger management issues," said the source.

"He’s gotten into violent fights there, and in a recent incident, he argued with a classmate. The fight escalated to the point where Pax punched the boy in the face. The boy was left black and blue, and scared out of his wits."

Angelina and Brad were so disturbed at Pax’s behavior, according to the source, they pulled him out of the school, where annual tuition can run from $15,000 to $20,000.

Adding to Pax’s issues, his biological mother was 25 and reportedly addicted to heroin when she gave birth. He lived in an orphanage until he was 3 1/2 – and that may be to blame for his disruptive behavior, the expert said.

Along with lack of discipline,the family’s nomadic lifestyle has most likely impacted the children, experts say.

Brad and Angie own at least five homes on three continents, and own a huge chateau in France.

The children not only bounce among those, they’re also dragged to their parents’ movie sets.

For now, Brad and Angie are struggling to rein in their kids’ behavior, and they’ve shelved plans to adopt again, said the source.

"With six young children so close in age, and trying to blend biological and adopted kids, it seems they’ve bitten off more than they can chew."