United Nations Secretary General Ban Ki-moon has noted with "deep concern" the recent reports of renewed heavy fighting in oil-rich Malakal, Upper Nile State, and the "catastrophic consequences" for civilian populations. Ban, in a statement released by his press office late on Thursday, urged all parties to the conflict to respect International Human Rights and Humanitarian Law and ensure that civilians are protected, warning that those responsible for crimes committed against civilians in South Sudan "will be held accountable." He reiterated the necessity for the parties to implement fully the January 23rd Agreements on Cessation of Hostilities and on the Status of Detainees, and to cooperate fully with the Intergovernmental Authority on Development (IGAD) Monitoring and Verification Mechanism, which the UN stands ready to support. The UN chief also called on all parties to respect the lifesaving work, to ensure unhindered freedom of movement of the UN Mission in South Sudan (UNMISS) and humanitarian workers, and to engage in serious political negotiations "as the only means for bringing peace to South Sudan." A political crisis erupted in the country on December 15th when government soldiers loyal to President Salva Kiir, who belongs to the Dinka tribe, accused his rival former Vice-President Riek Machar, who belongs to the rival tribe Nuer, of staging an attempted coup, and subsequently clashed with his supporters. Source: KUNA