President Obama expressed concern about growing tensions between Sudan and South Sudan when speaking April 2, 2012 to South Sudanese President Salva Kiir about the clashes in the border region between the two East African nations.



The president also expressed hope that a presidential summit that had been set for this week between Kiir and Sudan's Omar Al-Bashir will be rescheduled. A statement from the White House press office said Obama welcomed Kiir's commitment to moving forward with that meeting and to finding peaceful solutions for Sudan and South Sudan.



South Sudan claimed its independence from Khartoum in July 2011 after six years of autonomy and a referendum on nationhood. That victory came only after 20 years of violence, which claimed a high cost in loss of life and a lack of development at all levels.



But Sudan is engaged in further battles against an insurgent group in its southern states. Sudan is using heavy weaponry and aerial bombing to subdue rebels in the states of South Kordofan and Blue Nile. Secretary of State Hillary Rodham Clinton described that action as "disproportionate force" in comments to reporters March 27.



This violence has created a growing humanitarian emergency as civilians flee the fighting in search of safety across the border in South Sudan where there is little infrastructure and few resources to support them, according to an April 2 telephone briefing by U.S. officials involved in the aid relief.



Catherine Wiesner, deputy assistant secretary of state for population, refugees and migration, just returned from a visit to the remote region of South Sudan where refugee encampments have sprung up in recent months. She said the international humanitarian effort is building what is needed as it is needed. "So UNHCR [the Office of the U.N. High Commissioner for Refugees] and partners are fixing an airfield, they're building roads, they're drilling bore holes" for water. Wiesner said water is in very short supply for about 140,000 new refugees who have surged into South Sudan since the end of 2011.



"Agencies are in a race against time to get supplies in place," Wiesner said, before the rainy season begins in about a month and makes the region's poorly developed roads even more difficult for aid transport.



Wiesner said the World Food Programme (WFP) estimates that about 1 million people in South Sudan are severely "food insecure" at present, and that as many as 4.7 million will face some degree of food insecurity in the year ahead.



The United Nations and the African Union are in discussions with Sudan's government in Khartoum, trying to get permission for direct delivery of humanitarian relief to the internally displaced populations affected by violence in South Kordofan, where it is estimated another 200,000–250,000 people do not have enough to eat.



"We think [direct delivery of aid to Kordofan] is vital and it is very high priority," said Princeton Lyman, the U.S. special envoy for Sudan and South Sudan.



The violence in Kordofan and Blue Nile states disrupted the planting season in 2011, said an official with the U.S. Agency for International Development (USAID), and that's one reason for the high level of food insecurity.



Christa Capozzola, USAID's deputy assistant administrator for democracy, conflict and humanitarian assistance, said South Sudan's order in January for petroleum companies to stop oil production is another factor potentially worsening the crisis. The decision will reduce South Sudan's capacity to provide aid for its own people, many of whom are returning to the south after years of civil war ended with independence.



South Sudan has oil reserves, but the oil must be transported via pipeline from landlocked South Sudan across Sudan to the Persian Gulf and the markets beyond. South Sudan's government in Juba turned off the flow in early 2012, charging that the Sudanese are siphoning off hundreds of millions of dollars worth of oil.



"It's very important that both sides be extremely careful," Lyman said, "that neither crosses the line of attacking oil installations because I think that would deepen the conflict very much." He said it's important that the two governments discuss these issues "very candidly" in the interest of stability for both nations.



Despite the postponement of the summit at the presidential level, Lyman said, other talks are going on between the two nations, giving reason for optimism that tensions may ease.



"A meeting is under way of the Joint Political and Security Mechanism, a very important military-to-military discussion between the two countries under the auspices of the African Union," Lyman said. He praised the AU for its effort to mediate the dispute between Sudan and South Sudan.



The United States, the world's largest food-aid donor, has given more than $80 million to WFP to support the operations in Sudan and South Sudan. Another $6 million has gone to the UNHCR and the International Organization for Migration.