The UN's top human rights official warned South Sudan's leaders Wednesday they would be responsible should the "real danger" of famine become reality, amid mounting global outrage at a wave of atrocities. "I was appalled by the apparent lack of concern about the risk of famine displayed by both leaders," UN High Commissioner for Human Rights Navi Pillay told reporters. "The prospect of widespread hunger and malnutrition being inflicted on hundreds of thousands of their people, because of their personal failure to resolve their differences peacefully, did not appear to concern them very much."