Children in South Sudan have been forced to watch their mothers being raped and killed, the UN says.
Civilians have been tortured and mutilated, and villages destroyed on an industrial scale, it said.
These are some of the horrific abuses that a team of UN human rights investigators has detailed in a report published about the conflict in South Sudan.
The report says that some 40 officials may be individually responsible for war crimes and crimes against humanity.
Conflict between government factions has continued in South Sudan despite a peace deal signed in 2015.
The report will be presented to the UN human Rights Council in Geneva, but its real purpose is to provide evidence for a proposed hybrid court to try alleged war criminals.
Of the 40 senior officials identified as potentially responsible for atrocities, five are colonels and three are state governors.
But the court has still not been set up because South Sudan's parliament has not yet approved it.