Juba, South Sudan ? South Sudan celebrated its first day as an independent nation Saturday, raising its flag before tens of thousands of cheering citizens elated to reach the end of a 50-year struggle.

U.S. President Barack Obama called the day a new dawn after the darkness of war, while visiting dignitaries offered both congratulations and prodding for South Sudan and its former ruler, Sudan, to avoid a return to conflict over serious and unresolved disagreements.

“The eyes of the world are now on us,” said South Sudan President Salva Kiir, who was inaugurated during a scorching midday ceremony. Kiir stressed that the people of South Sudan must advance their country together and unite as countrymen first, casting aside allegiances to the dozens of tribes that reside here.

Saturday meant that South Sudan and its black tribesmen would for the first time be linked politically with sub-Saharan Africa. Kenya and Uganda are already laying strong economic ties with their northern neighbor, an oil-rich country that may one day ship its oil to a Kenyan port, instead of through the pipelines controlled by Khartoum.

“From today our identity is southern and African, not Arabic and Muslim,” read a hand-painted sign that one man carried as he walked through the crowds.

South Sudan first celebrated its new status with a a raucous street party at midnight. At a packed midday ceremony, the speaker of parliament read a proclamation of independence as the flag of Sudan was lowered and the flag of South Sudan was raised, sparking wild cheers from a crowd tens of thousands strong.

“Hallelujah!” one resident yelled, as other onlookers wiped away tears.

The U.S. and Britain, among others, announced their recognition of South Sudan as a sovereign nation.

“A proud flag flies over Juba and the map of the world has been redrawn,” Obama said in a statement. “These symbols speak to the blood that has been spilled, the tears that have been shed, the ballots that have been cast, and the hopes that have been realized by so many millions of people.”

Sudan President Omar al-Bashir, a deeply unpopular man in Juba, arrived to a mixture of boos and murmurs. He stood beside Kiir and smiled during the ceremony, and said in a speech that he respected the south’s choice to secede, even as he prodded Obama “to meet his promise and lift the sanctions imposed on Sudan.”

The U.S. has promised economic and political rewards to Khartoum if it allows the south to secede peacefully, but military standoffs in the contested border region of Abyei and new fighting in South Kordofan — a state in Sudan with many south-supporting residents — risk new north-south conflict. The U.S. has indicated that those issues need to be resolved before normalization of relations occur.

Obama said that South Sudan and Sudan must recognize that they will be more secure and prosperous if they move beyond past differences peacefully. He said the 2005 peace deal must be full implemented and the status of Abyei resolved.

In Khartoum, the former capital of the south, newspaper headlines bid goodbye, with one saying: “Time to Let Go.”

“Today we have decided it is time to move forward toward the future,” wrote Adil Al-Baz, the editor of Al-Ahdath independent daily. “Great people make use of big events to create new opportunities.”

The black African tribes of South Sudan and the mainly Arab north battled two civil wars over more than five decades, and some 2 million died in the latest war, from 1983-2005. It culminated in a 2005 peace deal that led to Saturday’s independence declaration.