A United Nations investigation identified three commanders suspected of bearing the “greatest responsibility” in the violence in Unity state between April 16 and May 24 that may amount to war crimes, it said in a report.
Elderly and disabled civilians were burned alive in the attacks on 40 villages, which appeared aimed at driving out opposition forces, it said.
“The perpetrators …must not be allowed to get away with it,” said U.N. High Commissioner for Human Rights Zeid Ra’ad al-Hussein in a statement.
Reiterating his call on the government and African Union to establish a hybrid court for South Sudan, he said the soldiers had slit elderly villagers’ throats, hanged women for resisting looting and shot fleeing civilians.
The U.N. report said opposition forces had also carried out armed attacks that caused civilian casualties.
The U.N. mission in South Sudan (UNMISS) said on May 17 it was sending 150 peacekeepers to protect civilians being targeted in clashes between the government and rebel troops in Unity state, which hosts abandoned oil fields.
There was no immediate reaction to the report from the Juba government.
On Monday, South Sudan rebels rejected a peace plan to reinstate insurgent leader Riek Machar as vice president, under a deal reached at talks in Uganda a day before.