KHARTOUM Around 655,000 people have been displaced or severely affected by fighting between the Sudanese army and rebels in two southern border states, the United Nations said on Wednesday.
Fighting broke out between the Sudanese army and rebels of the SPLM-North in South Kordofan state around the time of South Sudan's independence a year ago. It spread to nearby Blue Nile state in September.
The United States and aid groups have warned of famine in both states, especially in areas held by rebels.
Around 520,000 people have fled fighting in South Kordofan alone, Mark Cutts, the acting U.N. humanitarian coordinator in Sudan told reporters in Khartoum. More than 200,000 people have fled to South Sudan and Ethiopia, he said.
Sudan signed an agreement on Sunday with the United Nations and the African Union to allow aid into rebel-held areas in the two border states, but Cutts said details still needed to be negotiated.
"It's still early days," Cutts told reporters.
He said he expected progress in talks with Sudan soon but declined to say whether aid shipments would be under way by next month.
Ali Adam, a Sudanese humanitarian official, said safe passage for aid into rebel areas needed to be discussed first.
Sudan accuses South Sudan of supporting rebels of the Sudan People's Liberation Movement-North (SPLM-North), a claim Western diplomats find credible despite Juba's denial.
South Sudan often accuses Khartoum of bombing its territory, a claim denied by Sudan.
South Sudan seceded a year ago under a 2005 agreement that ended decades of civil war. But the neighbors remain hostile and came close to war again in April. The two sides reached agreement on oil transit fees on Friday, seen as a first step toward ending hostilities.
(Reporting by Ulf Laessing)