ABUJA - Rebel leaders pulled out of peace talks on the crisis in the western Sudanese region of Darfur on Monday, accusing the government of repeatedly breaching a ceasefire deal, spokesmen for their movements said.

The Abuja conference's African Union mediators, however, expressed the hope that the groups could be persuaded to change their minds and said they would attempt to reconvene the talks on Tuesday at 10:00 am (0900 GMT).

"We are suspending the talks until the situation improves," said Ibrahim Bahar of the rebel Sudan Liberation Movement, accusing the Khartoum government of ignoring a truce deal signed during a previous round of negotiations.

"The position of the two movements is the same. The situation on the ground in Darfur is deteriorating," Mohammed Ahmed Tugod, chief negotiator of the Justice and Equality Movement, told reporters as the conference broke up.

"We have no alternative but to come to this conclusion... in order to stop all the military activities going on in Darfur," he added.

The African Union's lead mediator, Sam Ibok, said that all the international representatives at the talks had advised against the walk-out because "there was no justification for such a suspension."

"The talks have not been suspended, we are reconvening at 10:00 am tomorrow," he insisted.

Meanwhile, Sudanese government spokesman Ibrahim Mohammed said: "Only negotiation and talks will solve the problem of Darfur. Withdrawal from the talks means more trouble for Darfur."

The Darfur region has been ravaged by civil conflict since February last year, when two armed opposition groups launched a rebellion against the government, demanding autonomy and a greater share of the nation's wealth.

Rebel leaders claim that the Arab-led government has marginalized and persecuted Darfur's mainly black African inhabitants.

Khartoum responded to the challenge by unleashing brutal pro-government militias. More that 70,000 have been killed and 1.6 million driven from their homes since the start of the fighting, according to the United Nations.

The Abuja talks were convened by the African Union in order to find a lasting political settlement to the crisis, but have made painfully slow progress while both sides regularly accuse the other of breaking the ceasefire.

Monday's meeting was the first face-to-face encounter between government and rebel envoys since the third round of talks began on Saturday.

Delegates heard from a spokesman for the African Union peacekeeping mission in Darfur that the number of registered and confirmed breaches of the ceasefire by fighters from both sides had risen to 52 since the start of the process.

Meanwhile the United Nations announced that two Sudanese working for the British charity Save the Children had been killed in a gun attack on their aid convoy in Darfur.