Sudan's government and rebels in war-torn Blue Nile and South Kordofan states have until April 30 to reach a peace deal, the African Union warned Wednesday.

The AU's peace and security council said in a statement it had called on its negotiators "to assist the parties to reach an agreement by April 30", although it made no mention of possible penalties should the two warring sides continue to disagree.

Talks, which began last month in the Ethiopian capital Addis Ababa after more than a year's break, have made slow progress.

A second round broke off on March 2 after only two days of meetings, with both sides blaming the other.

Rebels from the Sudan People's Liberation Movement-North (SPLM-N) have been fighting in South Kordofan and Blue Nile for nearly three years, a war which has affected over one million civilians, according to the United Nations.

Like the decade-old insurgency in Sudan's western Darfur region, the conflict has been fuelled by complaints among non-Arab minorities of neglect and discrimination by the Arab-dominated regime.

"There can be no military solution to the conflict," the AU added. "There is no alternative... than engaging in direct negotiations towards a comprehensive political settlement."