The UN's World Food Programme (WFP) said on Friday that it faces serious challenges in transporting food to deep-field locations in South Sudan due to access and security concerns. "We are very concerned about food security in South Sudan and the possibility of a food catastrophe developing over the coming year, given several risk factors, including ongoing conflict, mass displacement, trade and market disruption, food shortages, unusual livestock migrations, destroyed health facilities and disrupted farming," said the Geneva Spokesperson of the WFP Senior Public Information Officer Elisabeth Byrs in a press briefing. "Suffering has reached dire levels in some parts of South Sudan and assessments are ongoing now to give us a better sense of the food security situation. WFP and our partners are using every tool available to monitor changes in food security so we can respond to any sudden deterioration. We are working very hard to keep conditions from worsening further," she added. "WFP appeals to all parties to the conflict to facilitate unimpeded access to all those in need before conditions deteriorate even further, and we call on the donor community to increase their support for urgent humanitarian operations. "This is hampering our annual pre-positioning exercise, in which we stock up warehouses in areas that will become inaccessible when the rains start in April/May," she said. Despite immense challenges due to insecurity, including looting and commandeering of trucks belonging to commercial transporters contracted by WFP, "we have dispatched nearly 60,000 metric tons of food around the country since the start of the year," she added. As of April 22, WFP has provided food assistance to 702,213 people displaced as a result of the crisis. About 63,659 children under five years old were reached through blanket supplementary feeding in Central Equatoria, Jonglei, Lakes, Unity, Upper Nile, Northern Bahr el Ghazal and Warrap states. Byrs explained that the WFP continues to assist people sheltering in UN compounds and other IDP populations. More than 78,000 people are sheltering in UN compounds. Despite the heavy fighting that erupted in Bentiu (Upper Nile) on April 15, WFP has been able to quickly provide a 15-day food ration to around 22,000 beneficiaries, including wounded civilians at the IOM/IRC clinic and the new IDPs at the Rubkona UNMISS site. In Bor (Jonglei), and despite the volatile security conditions, over the last week, WFP and partners have distributed a total of 121 metric tonnes of assorted food commodities to 17,376 IDPs. During the past week, UNHAS facilitated the transport of 1,281 passengers and 219,927 kilograms of cargo, the relocation of 41 passengers and four medical evacuation. WFP has a current funding shortfall of USD 270 million out of an overall budget of USD 611 million for the Crisis Response Plan in South Sudan.