Congress passed a bill last week that restricts U.S. funding that fuels one of the world's most brutal forms of child exploitation.

Currently, an estimated quarter of a million children serve as soldiers for government forces, paramilitaries and rebel groups around the world.

In the past year, American tax dollars funded military assistance to six governments who use children to fight in their armed forces.

The Child Soldier Prevention Act, which Congress passed last week as part of a larger human trafficking bill, threatens to cut several types of U.S. military assistance to countries that continue to enlist or force children into their ranks.

"Americans' tax dollars should never contribute to training and arming children and sending them into battle," said Joseph Mettimano, vice president for advocacy at World Vision and a key adviser in the development of the Child Soldier Prevention Act. "This bill ensures genuine consequences for governments using children to fight their wars."

Child soldiers — some as young as 7 — are used as frontline combatants, porters, spies, human mine detectors and sexual slaves in some 20 conflicts on nearly every continent. The physical, emotional and psychosocial damage caused by children's exposure to armed conflict is severe and lifelong.

Each year, the Department of State's Country Reports on Human Rights identify government forces that recruit or use children in violation of existing international standards.

Countries listed in each year's report will be given two years to release the children within their ranks. During that time, the only military assistance the U.S. will provide will be specifically to help in that process. If, after that two-year period, there is evidence that child soldiers are still being used or recruited, all key forms of U.S. military assistance will be cut.

According to the Department of State, the countries that could be affected currently are Afghanistan, Chad, the Democratic Republic of Congo, Sri Lanka, Sudan and Uganda.