The United Nations has launched an emergency humanitarian effort, responding to a wave of violence in South Sudan that may have left thousands dead and an estimated 50,000 people in urgent need of aid.
The announcement of the response plan followed inter-tribal clashes in and around the town of Pibor in Jonglei state last month, sending tens of thousands of residents into the countryside.
Martin Nesirky, spokesman for UN Secretary-General Ban Ki-moon, said on Friday that a rapid response plan is now being finalised.
"The requirements already reported are already significant and around 50,000 people are estimated to be in need," he said.
He added that the UN mission had reinforced peacekeepers' presence in key areas and was conducting daily land and air patrols to deter potential violence. He said they were also working with the government of South Sudan to protect civilians.
Media reports have put the death toll in the clashes as high as 3,000, but Nesirky said his organisation could not confirm that number.
Lise Grande, the top UN official in the region, had earlier on Tuesday said the death toll could be anywhere from dozens to hundreds.
South Sudan became independent last July following a 2005 peace deal with now-northern neighbour Sudan.
But internal violence between the Lou Nuer and the Murle tribes is a reminder of the challenges the world's newest country faces inside its own borders.
Officials said the World Food Programme has delivered emergency rations to feed 1,000 people in Pibor for two weeks, and expects to reach 7,000 more people in the coming days. It has also distributed food packages for 2,000 internally displaced people at Boma region.
South Sudan has declared Jonglei state a national "disaster area".
Doctors Without Borders (more commonly known by its French name, Medecins Sans Frontieres), the main health care provider for the estimated 160,000 people in Pibor county, has suspended its operations after the clashes forced it to evacuate staff.
"Parts of the town have been burnt, our facilities were completely looted, but people are coming back and are not afraid any more, it is stable now," Parthesarathy Rajendran, the MSF's head of mission, said after visiting Pibor.
"There are enormous needs, some people need every single item. Our first priority will be medical care, but we are planning to provide non-food items as well so people can start rebuilding," he added in a statement Friday.
"There is a long history of cattle-raiding between these ethnic groups - the Lou Nuer and the Murle - going back years," Jon Temin, the director of the Sudan programme at the United States Institute of Peace, told Al Jazeera.
"Most recently, there was a large attack in the other direction, the Murle against the Lou Nuer, in August that killed an estimated 600 people."
He said that in addition to ethnic divisions, there is a strong economic element to the clashes, as "cattle are a real store of value - a currency, in some ways, in these rural parts of South Sudan. Cattle are also very important in paying dowry, the bride-price that men have to pay in order to get married. And there has been a real escalation in dowrys recently, making the need for cattle even greater."