Government troops are responsible for most of the killings and rapes of children carried out in South Sudan, the United Nations said on Monday.
"I am especially alarmed by the rampant levels of grave violations committed by government security forces," Virginia Gamba, the UN Special Representative for Children and Armed Conflict, told the Security Council.
The Sudan People's Liberation Army (SPLA) is said to have carried out nearly 80 percent of the 987 killings or maimings of children documented by the UN between October 2014 and June 2018.
The SPLA was also responsible for more than 90 percent of 658 verified incidents of sexual violence against children during that period, the report adds.
Most of these cases involved "gruesome gang rapes," the UN special representative states.
"The full scale of sexual violence affecting children is believed to be under-reported, in particular against boys, owing to fear of stigmatisation and reprisals and to the lack of adequate support services and avenues for accountability," Ms Gamba's report notes.
The UN cites a rampage by SPLA soldiers and "armed youth" in Unity State six months ago in which "sexual violence was used extensively during indiscriminate attacks on villages."
Two years earlier, SPLA soldiers raped or gang-raped 34 girls and 30 women from villages in Koch County in Unity State, the report says.
"Sexual violence was used as a form of collective punishment to instill fear and humiliation within communities," the UN observes.
In August 2016, 10 girls fleeing to a UN civilian-protection site in Bentiu in Unity State "were stopped on the way there by some 20 SPLA soldiers and taken into the bush and raped repeatedly," the report adds.
Most of the attacks on schools and hospitals documented in the period covered by the report were also said to be the work of the SPLA.
Factions of the armed opposition recruited and used a sizable number of child soldiers, the report says.
The UN counted 1447 children, including five girls, among forces loyal to deposed Vice President Riek Machar. Groups associated with Taban Deng Gai, formerly a prominent figure in the armed opposition and now one of the country's vice presidents, recruited and fielded 801 children, including 46 girls, according to the report.
The SPLA accounted for more than 40 percent of the total number of 5723 child soldiers reported to be in the ranks of armed groups.
"Children were used to commit atrocities against civilians, including other children," the report says.
Poverty was a main reason why children became members of the South Sudan government army, the UN finds.
"Several children stated in interviews that they had joined SPLA owing to poverty, since they were paid between 700 and 1,500 South Sudanese pounds per month (between 5 and 12 United States dollars) by SPLA," the report recounts.
There are indications that the South Sudan government may behave more responsibly toward children in the future, the report points out.
Earlier this year, army leaders agreed to allow UN units to visit all military barracks to screen and release child soldiers. But only such mission had taken place as of June of this year, the report notes.