South Sudan's government has recruited child soldiers in the past week to prepare for a renewed conflict, according to an internal United Nations document.
The document says a senior politician appointed by President Salva Kiir led the recruitment of an entire village of boys using intimidation.
Some were as young as 12 years old. It was not clear how many children were involved.
Armed groups in South Sudan often coerce children to join their ranks by threatening to confiscate their family's cattle, a key source of wealth and status in this pastoral society.
The UN document indicates that the recruitment of children took place shortly after the UN Security Council a week ago approved sending an additional 4,000 peacekeepers to the East African country to protect civilians after renewed fighting in the capital, Juba, last month.
Separately, UNICEF on Friday announced that at least 650 children have joined armed groups in South Sudan this year alone.
Around 16,000 child soldiers have been recruited since civil war began in December 2013.
Army spokesperson Lul Ruai Koang said youth who join the military are not forced. He said he was not aware of the recent recruitment of children.
South Sudan's military and opposition forces have made repeated promises to address allegations of child recruitment, but both sides have continued recruiting since July's outbreak of violence, according to Justin Forsyth, UNICEF's deputy executive director.
"They believe they can easily control and manipulate young minds," Forsyth said. The children then "can commit atrocities, and they will do what they are told."
Child soldiers are defined as anyone recruited to join armed groups under the age of 18, and the International Criminal Court considers the recruitment of those under 15 to be a war crime.
In an interview this month in Unity state, one former child soldier said he had expected to do cooking and cleaning in the army when he joined at age 16 but instead was sent to fight on the front lines.
"If you go to the front line, two things would happen: either you will kill someone or you will be killed," he said.
He was released from the army a few months ago, one of more than 1,000 child soldiers who have been demobilised from different armed groups as part of a UNICEF program.
"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."
