JUBA, Sudan, Jan. 9 -- JUBA, Sudan, Jan. 9 (UPI) -- Flags are raised on every street, sticking out of nearly every passing car and featuring in the dress of many a voter.

As the sun cast its first rays Sunday across Juba, the capital of Southern Sudan, seemed draped in the flag, the symbol of what is expected to be Africa’s newest nation. The people who lined up in Juba to vote were among an estimated 4 million Southern Sudanese voters expected to cast ballots on the measure to decide whether Southern Sudan should break off from the rest of the country.

As early as 4 a.m., zealous voters trekked to polling stations dotted across neighborhoods in Juba and throughout the country. Instead of a staid political event, the referendum has the atmosphere of a cultural festival with traditional folk songs filling the air.

Southern Sudanese President Salva Kiir Mayardit was among the first to vote, arriving at a polling station near the mausoleum of John Garang, the popular southern Sudanese leader who was killed in a helicopter crash just weeks after he signed the 2005 Comprehensive Peace Agreement with the northern Sudanese government. Kiir arrived mausoleum shortly before 8 a.m. Amid tight security, he called for calm as he urged more voters to turn out.

“This is a historic moment that the people of south Sudan have been waiting for,” he said. “I call on all south Sudanese to be calm and patient,”

Hollywood star George Clooney and U.S. Sen. John Kerry, D-Mass., were among those in audience. Garang’s wife was also there.

Some of the voters camped outside polling stations and began forming lines as the countdown to the referendum wound down to zero at midnight.

Joyce Hifita left her home before 3 a.m. and made her way to the polling center. She cast her vote minutes after Kiir.

“I came here very early,” she said. “I feel more special because I’m voting where my leader John Garang is resting.”

Across other polling stations in the city, lines zigzagged and doubled over.

“We are all here to speak out,” said John Unak, a policeman. “This day is beautiful and great for the sons and daughters of the south.”

Dance troupes took their show to the polling centers, exciting an already hyper environment. At the Garang mausoleum, youthful entertainers broke into random song and dance every few minutes as journalists clicked away on their cameras.

International observers jostled for space with the sheer number of eager press. Observers from the European Union and the Carter Center monitored voters as they cast their ballots. Other observers in the referendum include the region’s Inter-Governmental Authority on Development, representatives from the neighboring states and a network of local civil society groups.

“This is the first real test for southern Sudan,” said Yasir Moro Keny, a local observer. “If South Sudan gets it right in these first few steps, then things will work out well.”

Also among the observers was Darfur’s former agriculture minister, Omar Fur. Fur, now an SPLA official, said that he was there to “witness this great moment of history” which he hoped would inspire change in the rest of Sudan.

“I’m not Southern Sudanese, so I cannot vote,” he said, “but am here because this is a new dawn. I can’t miss this moment in history. If the regime in Khartoum doesn’t want reform, then they can expect something like this in Darfur and elsewhere.”

Many voters took advantage of the cameras and microphones to make their voice known. Language barriers mattered little as they flashed ink-stained fingers -- a sign of having voted -- and waved voter’s cards, grinning widely at the cameras.

“You can think of it as a family reunion,” said Daniel Dongrin, a geologist who returned to Sudan from Vancouver, Canada. “Three-point-nine million brothers and sisters have come together today to cast their thought in stone.”

Most businesses remained closed and there were very few cars on the streets. Security outfits fanned out across the entire city with sirens blaring loudly and soldiers on alert. Ambulances were on standby in all polling stations.

Voting was expected to close at 5 p.m. but will resume Monday and continue through Saturday. A preliminary tally of results is expected by Feb. 1. The final count is expected to be released Feb. 6 if there are no appeals against the tallied results.

Southern Sudan Referendum Commission Chairman Justice Chan Reec Madut was upbeat about the voter turnout.

“We have never witnessed this size of a turnout before,” he said, “not even during the last (April’s) general election!”