This holiday season, children across America will unwrap presents of virtual combat -- best-selling video games that simulate battle, with names like "Gears of War" and "Far Cry Vengeance."
But elsewhere, other children will play real war games.
Across Asia, Africa and Latin America, children as young as 6 years old are being forced into life as child soldiers.
Children you'd expect to see in a classroom are carrying AK-47s instead of books. Adult instructors are teaching their tiny pupils how to shoot to kill, instead of arithmetic.
The film "Blood Diamond," which stars Leonardo DiCaprio and will open nationwide in theaters Friday, follows the story of a Sierra Leone man who loses his young son to war funded by the sale of diamonds.
In reality, life as a child soldier is just as horrifying and perhaps more brutal than the story depicted in the DiCaprio film, as illustrated in footage of real child soldiers shown exclusively to ABC News.
"They'd whip us as punishment. If you made a mistake, they'd whip you up to 70 or even 120 times," said one child soldier in the Democratic Republic of Congo.
"They captured us as we were fleeing. If you refused [to join the soldiers,] they'd shoot you dead," said another child in the Congo who was interviewed by Amnesty International.
Under international law, the recruitment and use of soldiers younger than 18 years old is prohibited.
The recruitment and use of children younger than 15 is considered a war crime.
Yet in several countries -- particularly Sri Lanka, the Congo, the Ivory Coast, Colombia and Afghanistan -- the use of child soldiers is widespread.
According to the U.N. Children's Fund, roughly 300,000 child soldiers worldwide are participating in 30 armed conflicts.
Jimmie Briggs, author of "Innocents Lost: When Child Soldiers Go to War," said child soldiers were often used instead of adults because they were usually immature, very pliable, and had fewer inhibitions.
"[Their] moral conscious is not as developed as an older person's," Briggs said to ABC News. "You can turn a child into a soldier very easily."
One might assume that child soldiers would have problems maneuvering modern weapons, but Briggs offered a different view.
"AK-47s and hand guns are simple enough and light enough that a child can load it effectively," he said. "I've seen it firsthand in Colombia, Africa and Asia."
An administrator at one Congolese demobilization camp that reintegrates child soldiers to civilian village life concurs.
"[Children] ask for nothing and are considered excellent fighters," he said on the footage shown to ABC News. "They are not scared by dangers. … They're prepared to do anything."
Recruits Without Choice
Larry Cox Executive Director of Amnesty International, told ABC News that most children involved in these conflicts were pawns who did not join national armies or guerrilla forces willingly.
"They fight because often they have no choice," he said. "They're abducted. They're seized by armed groups that break them down."
Child soldiers, Cox said, are often taken to intensive training camps, where they are "drugged and forced to perform horrendous acts. … Killing people they know, sometimes their own parents."
"You can imagine the psychological trauma of that," he said. "They no longer have any ties to anyone other than the people who've made them do this. They have no choice but to remain loyal."
A Checkered Rehabilitation
If there is hope for child soldiers, it is because many of them want to go back to a normal life.
They want an education and a future.
"I'm not a thief or a killer anymore. I want to have a good life and return home and live well," said one child. "I don't want to walk by people who are afraid of me and say: 'There's the soldier, the killer.' I want to get help. … I just want to return home and for everything to be OK."
But lack of opportunity holds them back from recovery.
Poverty and the destruction of war mean that many children who leave the army find a home with little food and no access to education.
In extreme cases where the immediate need of food, clothes and shelter cannot be met, war is sometimes the relatively better option for a young child.
"If I return from the army, I have nothing to eat and we don't have any means at home. I'll go back to the army," said one former soldier.
Most international organizations only operate on the outskirts of cities, said one aid official who assists child soldiers.
In more isolated communities, their safety is not assured.
Some villages have a hard time welcoming child soldiers back. They may be children, but because of their time spent fighting and pillaging they tend to be looked upon as predators. And for that, they are often denied forgiveness.
Once child soldiers are out of the combat zone, the risk of re-recruitment is high.
When asked whether he had considered rejoining the army, one child soldier said he had thought about it often.
"Some people came looking for former soldiers, for child soldiers. … It had been my intention to return to the army," he said. "Even if my mother and family could take me back, they don't have the means to send me back to school. Here, the only thing I can do is steal. … All I can do is roam around the streets."
Another Congolese child echoed that same sentiment.
"I'd rather fight for my country than stay home with no food," he said.
Facing abject poverty and the rule of the gun, parents can find themselves unable to help their own children.
"If he stayed with us, the soldiers would come for him and beat us up. So we were afraid and we chased him [her son] away," said one child's mother.
"I'm not financially able, and I'm alone," said the father of a different child soldier. "And I'm afraid of the mentality he [his son] may have acquired in the army. I'm not sure whether he can change and go back to being a regular person."
In addition to the psychological traces left behind by the experience of being a young soldier, the physical effects on a child can be lasting and devastating.
Many girls abducted into combat life are sexually abused and placed at very high risk of contracting venereal disease and HIV/AIDS, said Amnesty's Cox.
"Often the armies who've taken these young women treat them as if they are sexual slaves," he said. "They're very reluctant to give them up."
What You Can Do to Help
While the problem of child soldiers has no easy solution, there are ways an individual American can have impact.
So what can you do to help?
You can also contact your elected officials to voice your opinion on the issue.
Find your U.S. senator at http://www.senate.gov/general/contact_information/senators_cfm.cfm or your representative in Congress at http://www.house.gov/writerep/.
Purchasing jewelry made with non-conflict-related diamonds also can help by cutting off financing for wars that employ child soldiers.
Ask your jewelry store whether the merchandise it sells uses nonconflict diamonds. Follow this link to learn more information about how you can take action.
ABC News' Lauren Pearle contributed to this report.