The oil-rich border area remains disputed between Sudan and South Sudan . South Sudan fought a two-decade civil war against the government in Khartoum , which led to secession . In a statement released on Monday, the U.N. Security Council said it was "gravely concerned" about reports of violence in Jonglei state. The oil fields account for about half of Sudan 's oil production .
The oil-rich border area remains disputed between Sudan and South Sudan . In a statement released on Monday, the U.N. Security Council said it was "gravely concerned" about reports of violence in Jonglei state. The oil fields account for about half of Sudan 's oil production .