Sudan has delayed the registration of voters for January's referendum on secession for the south until November, raising tensions over the timetable. The chairman of the referendum commission said this was to allow for staff training and delivery of forms.

Tanzania's former President Benjamin Mkapa, appointed by the UN to oversee the vote, has said many challenges lie ahead . But he said if all parties were willing, the timetable would be met. The referendum was part of a 2005 peace deal to end two decades of conflict between the north and oil-rich south in which some 1.5 million people died.

Analysts fear there is a risk of the conflict restarting if southerners feel that Khartoum is trying to delay or disrupt the vote in the oil-rich region - one of the world's poorest and least developed regions. Chairman of the Southern Sudan Referendum Commission, Muhammad Ibrahim Khalil, said the registration had been delayed by three weeks till 15 November.