The Sudanese government and rebels are unlikely to reach agreement on the main issues at peace talks aimed at ending their 15-year civil war, African diplomats said on Wednesday.

The diplomats, who declined to be identified, said the sides were deadlocked over what constituted south Sudan. Talks resumed on Tuesday and should run until Thursday.At the last round in the Kenyan capital, Nairobi, in May, the government said it would only accept a referendum of self-determination for the south in the three provinces of Bahr el Ghazal, Equatoria and Upper Nile.

The Sudan People's Liberation Army says the referendum should also include Southern Kordofan, Southern Blue Nile and Abyei provinces.

"The government rejects this; it says these three provinces are outside the jurisdiction of southern Sudan," a diplomat said.