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 reports the BBC.
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 deed which ended the two-decade north-south civil war.
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, said 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.
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.