Sirte, Libya: The Sudanese government declared an immediate unilateral ceasefire in Darfur yesterday at the opening session of talks aimed at ending four and a half years of violence in the region.

"We announce a ceasefire from this moment, and we will respect it unilaterally," Sudanese presidential adviser Nafie Ali Nafie told the gathering in the Libyan town of Sirte.

A Darfur rebel leader also expressed doubts yesterday about a unilateral ceasefire, saying Khartoum had failed to honour such undertakings in the past.

"The government has already said several times since 2004 that they observed a ceasefire. They again spoke like this [yesterday]. We have our doubts," Ahmad Ebrahim Diraige, leader of the Sudan Federal Democratic Alliance, told Reuters.

Diraige earlier made a speech at the peace talks on behalf of all the rebel groups present in Sirte.

Doubts

On the eve of the African Union-United Nations-mediated talks, two main rebel groups - the Justice and Equality Movement (JEM) and the Sudan Liberation Army Unity faction - said they would not attend.

The decision emerged after another rebel chief, Abdul Wahed Mohammad Al Nour, founder of a third group, the Sudan Liberation Army (SLA), said he would not travel to Libya for the talks. JEM-SLA Unity represent the biggest military threat to the Sudanese government and Al Nour has the most popular support among Darfuris.