The African Union expressed "deep regret" on Thursday after two Darfur rebel factions missed an AU deadline to sign a peace deal aimed at ending the three-year-old conflict in Sudan's remote west.
The AU has raised the spectre of UN sanctions against the Sudan Liberation Army (SLA) faction led by Abdel Wahed Mohammed al-Nur and the rebel Justice and Equality Movement (JEM) if they did not sign before May 31.
In a statement, AU Commission Chairman Alpha Oumar Konare noted "with deep regret" that last-minute efforts to get the two factions to sign the May 5 deal had failed.
It said the AU's Peace and Security Council will now decide whether to take punitive action against the groups. The council was expected to meet in the coming days. In the meantime, efforts were under way to try to break the impasse and win support for the accord from all rebel factions.