Formal negotiations are due to start in Nairobi on Monday, in the latest round of peace talks between the Sudanese Government and representatives of the rebel Sudan People's Liberation Army.

The talks will be taking place amid angry protests from the SPLA that government planes have bombed a southern town.

A rebel spokesman, Samson Kawaje, said the attack on the rebel-held town of Yei had violated the ceasefire agreement which was extended on Saturday for another three months.

Mr Kawaje said the bombing did not create a good climate for the talks.

Diplomats have said the two sides are no closer to a compromise than previously, as they begin their fifth round of talks.

More than 1.5 million people have died in fighting or war-related famine in 17 years of civil war in Sudan.

Autonomy proposal

The SPLA rebellion against the Islamist government is based in the south of Sudan, where the population is predominantly Christian or animist.

The government has refused to meet the rebels' demand for the suspension of Islamic Sharia law.

While both sides have agreed to a referendum on autonomy for the south, differences remain over how to draw the boundary between south and north.