The international human rights organization, Human Rights Watch (HRW) says South Sudan's army used child soldiers during recent fighting against opposition forces in violation of international law.
HRW reports the government used child soldiers in renewed fighting in mid-August in Bentiu, the capital of Unity state, as well as in the neighboring town of Rubkona.
Eyewitnesses who fled the fighting told HRW they saw dozens of children in military uniform and armed with assault rifles who were deployed alongside government soldiers.
Skye Wheeler, a Human Rights Watch researcher in Juba, reports that boys as young as 12 years of age spoke with her about their experiences working for the Sudan' People's Liberation Army (SPLA).
During an attack last Friday by opposition forces on Bentiu, capital of oil-producing Unity state now under government control, Wheeler said large numbers of civilian women seeking refuge at the UN base "told us that they saw child soldiers being used by the government defending the town."
The armed children were also observed by Wheeler, her colleagues, and other humanitarian workers and UN personnel.
"Everyone has seen them," Wheeler says. "They are being used openly by the government in these towns for the last several weeks. And kids that we spoke to also said that they and other children had been posted out to defend areas around the edges of the town for the last few weeks as well," the researcher says.
Wheeler says the government is breaking international law and committing war crimes because the children are 15 years of age and under.
The Sudanese army is a national army that only recently rose from a rebel force. Wheeler says the nation took major steps at independence three years ago to end the practice of recruiting children to war. After independence they were, she said, "releasing them, demobilizing them out of their army, and getting them back home with their families."
She expressed sadness that both sides in the South Sudan conflict have taken a step backward. Both forces - the government as well as the opposition - have been recruiting children, Wheeler acknowledged.
In part, the problem reflects the nature of the national population: a major percentage of South Sudan's population is children.
Wheeler says humanitarian agencies recognize the problem - particularly in Bentiu - and referred to a recent statement by Medecins Sans Frontieres that in Bentiu "kids are dying every day over the last few months.
"There are wars going on, there's battling going on. We've repeatedly seen in this conflict how civilians including children have been targeted and killed because of their ethnicity or their perceived allegiances," says Wheeler.
"It's a very young population," Wheeler says. "And kids have suffered horribly in this conflict. The humanitarian situation in South Sudan is devastating. There are 1.5 million people displaced from their homes.
Recent heavy rains have flooded large areas of the IDP camps in Bentiu and Malakal, forcing people to wade in shin-deep filthy water just to get from place to place. "People are living in horrible conditions in IDP camps," she says. Such conditions take a heavy toll on the children.