|Among the first to vote was Salva Kiir, the president of southern Sudan
Southern Sudanese have turned out in droves to vote in a historic referendum to decide whether they want to secede from Sudan or remain united.
The week-long poll started on Sunday at 8:00 local time [05:00 GMT] across Sudan. It is also being held in eight other countries that have substantial numbers of southern Sudanese.
Chan Reec, deputy head of the South Sudan Referendum Commission, hailed the massive turnout in the first hours of the week-long independence vote.
"I can't express it. This is the size of turnout we have never witnessed before, even during the election," he said, referring to last April's presidential, parliamentary and state elections.
"There is singing, there is dancing, this is a day like no other in the history of the people of south Sudan," he said.
Among the first to vote was Salva Kiir, the president of southern Sudan.
Kiir appeared early at a Juba polling centre near the simple mausoleum of John Garang, who led the south to a 2005 peace deal that ended a 22-year war with the north. Garang died in a helicopter crash soon after the deal was signed.
Addressing people gathered at the voting centre after he cast his ballot, Kiir paid tribute to Garang.
"Dr John Garang, and those that died with him in the struggle, are here with us today and we hope that they did not die in vain," Kiir said.
US senator John Kerry is in Sudan as President Barack Obama's special representative
"This is the moment you have been waiting for," he told the huge crowd inside and outside the memorial grounds.
He asked them to be patient about voting after having waited for more than 50 years to choose their own destiny.
"Even if you cannot vote today, you have six more days to vote."
Kiir said that in no way should the vote be jeopardised, telling the security forces to protect all the people, especially people from the north.
Acuil Tito Madut, Southern Sudan's inspector general of police, told Al Jazeera that the security situation in all of south Sudan was calm, "except for the skirmishes in Abyei yesterday".
At least one person was reported dead on Saturday after violent clashes between Misseriya tribesmen and southern security forces in the disputed Abyei border region.
"We are still observing the situation there," Madut said.
He confirmed that a large number of people had turned out to vote, and that voting was going well throughout the region.
"We do not think all the people who have turned out today can vote by the end of polling at 5pm. They will have to vote tomorrow."
Al Jazeera's Mohammed Adow, reporting from Khartoum in the north, said voting took off to a slow start.
"There were no queues. Most of the 70 polling stations in the capital have more polling officials and observers than voters," he said.
"Officials say the knowledge that they have six more days to vote might be keeping voters away during the first day of the historic polls."
A total of 3.9 million southerners have registered for the self-determination vote that may lead to the partition of Africa's largest country.
The breakdown of the registrants is: Southern Sudan, 3.7 million; northern states, 116,000; and the diaspora spread over eight countries, 60,000.
Nhial Wei, a young student in the south, told Al Jazeera that he was proud of the moment. "But we should not count our chickens before they hatch," he said alluding to the challenges that lie ahead for this would-be young nation.
John Kerry, a US senator, is in Sudan to monitor the polls and act as President Barack Obama's special representative.
Kerry watched Kiir cast his vote and said that the referendum represented a "new chapter" for Sudan.
Hollywood star George Clooney also watched Kiir as he cast his ballot, and described the launch of the referendum as a "great day for all the world".
On the ground, to see firsthand that the referendum passes off without any incident, are 1,400 international observers spread across Sudan.
UN flights were busy throughout the past few days to take the observers to remote areas of a region the size of Texas state in the US.
Prominent among foreign poll observers are Jimmy Carter, former US president and Kofi Annan, the former UN secretary-general.
Visiting a polling station at the St Bakitha Kator Primary School in Juba, both Carter and Annan said that they were happy with conduct of the poll so far and the enthusiasm shown by the people.
|Jimmy Carter, former US president and Kofi Annan, former UN head, visited polling stations
"The world is watching and the people of Darfur especially are watching this democratic exercise very keenly," Carter said.
He said the best way forward would be for both regions of Sudan to have a soft border between them.
"People have had enough of war. They want to avoid conflict," Annan said.
Annan told Al Jazeera that the Sudan People’s Liberation Movement, the ruling party in Southern Sudan, had lots of experience, unlike other armed groups that transform into governing parties.
"They have to learn from the mistakes of others and hope not to repeat them," Annan said.
Vote counting will be done on a daily basis and results will be displayed at individual centres. While the preliminary results will be announced from Juba, the final result will be announced in Khartoum.