Members of South Sudan’s government committed human rights violations “amounting to war crimes” in the country’s southwest, the UN said on Friday, urging investigations against dozens of individuals, including for abuses against children. The world’s newest nation has suffered from chronic instability since independence in 2011, with the UN warning last month that it risked a return to war as interethnic violence and political infighting threaten an already fragile peace process. At least 440 civilians were killed in brutal fighting between rival militias in the country’s southwest between Jun…