The African Union (AU) increased the pressure on two rebel factions to sign a peace agreement for Sudan's Darfur region by threatening international sanctions if they did not come around.
Only one of the three Darfur rebel factions signed a May 5th accord with Khartoum to end fighting that has killed tens of thousands of people, and officials fear the two holdouts could instigate violence to scuttle the deal.
Alpha Oumar Konare, chairman of the AU commission, urged a faction of the rebel Sudan Liberation Army (SLA) led by Abdel Wahed Mohammed al-Nur and the smaller Justice and Equality Movement to sign the deal unconditionally.
"Should they embark on any action or measure likely to undermine the Darfur peace agreement, especially the ceasefire provisions, the council should take appropriate measures . . . including requesting the UN Security Council to impose sanctions against them," he said in a statement.
The warning came as the AU's Peace and Security Council met in Addis Ababa to discuss how to push forward the peace process in Darfur, which UN Secretary-General Kofi Annan says is the world's worst humanitarian crisis.
Mr Konare called for more AU troops to be sent to Darfur and urged Khartoum to produce a plan to disarm pro-government militias accused of a campaign of murder and rape that has driven more than two million people into camps in Darfur and neighbouring Chad.
In another sign of a concerted drive by the AU to pull the rebels into the deal, its chief Darfur mediator warned Mr Nur he would become irrelevant unless he accepted an agreement already signed by his rival Minni Arcua Minnawi, leader of the biggest SLA faction.
Mr Nur has come under increasing pressure to sign the deal, but he has set conditions that he says must be met first. Although he is weak militarily, he represents Darfur's largest Fur tribe.
Mr Nur demands greater compensation from Khartoum for Darfur war victims, more political posts for the SLA and greater involvement by the movement in the disarmament of pro-government militias.
The peace agreement has provoked violent protests in Sudan by refugees who say it is not enough to protect them, and criticism from the Sudanese opposition that the parties were pressured into signing an ill-considered deal.