A first round of talks Sunday between presidents Omar al-Bashir of Sudan and Salva Kiir of South Sudan ended without announcing an agreement, the Sudan Tribune announced.
The talks are in Addis Abba, Ethiopia.
The meetings were called to discuss an African Union proposal on who is eligible to vote in an October 2013 referendum on the Abyei region.
South Sudan wants only the dominant Ngok Dinka and members of the Misseriya tribe to be able to participate in the referendum. Khartoum wants to qualify anyone who has lived in the region for six months.
Luka Biong Deng, co-chairman of the Abyei Joint Oversight Committee, said Abyei, a prime oil-producing region, would become a state with special status regardless of whether residents there voted to remain in Sudan or join South Sudan.