People in Southern Sudan have begun voting in a landmark referendum on independence from the north. The week-long vote is widely expected to result in Africa's largest country being split in two. As people flocked to the polls, South Sudanese leader Salva Kiir said: "This is an historic moment the people of Southern Sudan have been waiting for." The poll was agreed as part of the 2005 peace dead which ended the two-decade north-south civil war. Wilson Santino, a voter queuing up in the southern capital Juba, told AFP news agency: "This is a new dawn because we vote for our freedom. "We have been fighting for too many years but today this vote for separation is also for peace." On Saturday, Mr Kiir said the referendum was "not the end of the journey but rather the beginning of a new one". He was speaking in Juba alongside US Senator John Kerry, who has been in talks with both northern and southern leaders attempting to smooth the voting process. The run-up to the vote was marred by an attack by rebels on Southern Sudan's military in the oil-rich Unity state. Col Philip Aguer, a military spokesman, told the Associated Press on Saturday that his troops had retaliated and killed four of the rebels. UN officials confirmed that they had received reports of an attack in the area, but did not say which side had suffered the fatalities. EU-style bloc? On Friday, Sudan's President Omar al-Bashir warned the south would face instability if it voted to secede. In an interview with the Arabic news channel al-Jazeera, he said he understood why many southerners wanted independence, but he expressed concern at how the new nation would cope. "The south suffers from many problems," he said. "It's been at war since 1959. The south does not have the ability to provide for its citizens or create a state or authority." Mr Bashir said southerners living in the north would not be allowed dual citizenship, and floated the idea of the two nations joining in an EU-style bloc. He also raised the issue of Abyei, an oil-rich region with disputed borders. He warned that if southerners seized the region for themselves, it could lead to war. Analysts say Mr Bashir is under intense pressure from northern politicians, who fear that secession of the south may lead to a further splintering of the country. North and south Sudan have suffered decades of infighting in conflicts driven by religious and ethnic divides. Southern Sudan is one of the least developed areas in the world and many of its people have have long complained of mistreatment at the hands of the Khartoum government. Turnout in the referendum will be important, as the 2005 peace agreement stipulates a quorum of 60% of the 3.8 million registered voters.