Both the government and the rebels use blackmail to coerce families into giving up their children to fight. The International Criminal Court considers it a war crime to recruit anyone under the age of 15 for combat.
South Sudan's government is recruiting child soldiers - again - as the world's youngest nation appears to be lurching towards renewed civil war.
A UN document revealing the initiative said President Salva Kiir appointed a senior official to lead the recruitment effort. It says government forces, or their supporters, recently used intimidation to recruit an entire village of boys, some as young as 12 years old.
UNICEF's deputy executive director Justin Forsyth recently returned from South Sudan.
"The dream we all shared for the children of this young country has become a nightmare," he said.
It's unclear how many children were taken, but armed groups - both government and rebels - often resort to blackmail, threatening to seize a family's cattle, to recruit children for war.
Cattle are an integral source of wealth and status in their bucolic society.
The UN document claims the recruitment drive began shortly after the UN Security Council approved sending 4,000 more peacekeepers to the East African nation last week.
That vote was propelled by renewed fighting last month in the capital, Juba.
Thousands of child soldiers
Separately, UNICEF says at least 650 children have joined armed groups in South Sudan this year alone. Overall, around 16,000 child soldiers had been recruited since the country's initial descent into civil war in December 2013.
Army spokesperson Lul Ruai Koang insists underage children who join the military do so voluntarily. He said he was unaware of new recruitment efforts aimed at children.
Both sides in South Sudan's conflict have repeatedly promised to address allegations of child recruitment, but they continue such recruitment efforts. The outbreak of violence in July was just the latest round, according to Forsyth.
"They believe they can easily control and manipulate young minds," he said. The children then "can commit atrocities, and they will do what they are told."
Child soldiers are defined as anyone recruited to join an armed unit who is under 18, and the International Criminal Court considers the recruitment of anyone under 15 to be a war crime.
One former child soldier in South Sudan said he expected to be cooking and cleaning when he joined the army at age 16, but he wound up being ordered into combat.
"If you go to the front line, two things would happen: either you will kill someone or you will be killed," he said.
He is one of more than 1,000 child soldiers recently demobilized as part of a UNICEF effort.
"I was not happy because I was given a gun when I was so young," the teen said. "If you are afraid, the commander will beat you."
bik/jil (AP, Reuters)