South Sudan set for referendum

• The Sudanese President last week pledged to help build a secure, stable and "brotherly" state in the south if it votes for independence.
• More than 3.5 million southerners are registered to participate in the referendum due to begin on Sunday, which will give them the chance to vote on whether to remain united with the north or secede.
• The vote is a key plank of the 2005 north-south peace deal that ended a devastating 22-year civil war in which some two million people were killed and another four million displaced.
• Sudan's oil-rich mainly Christian south is widely expected to choose independence from the mainly Muslim north