A day after the jubilation of South Sudan's independence proclamation, the U.S. ambassador to the U.N. warned Sunday of a "real risk" that the north-south peace process could unravel unless outstanding issues such as oil and border demarcations are quickly resolved.
Celebrations rang out Saturday in the South Sudan capital of Juba, the first day of independence after decades of civil war between Sudan's north and south. Some 2 million people died in the most recent war, from 1983-2005.
On Sunday, the capital appeared hungover from its massive celebration, though small groups of people still sang and danced on street corners. The new country's national anthem played from speakers and cell phones.
The joy of independence day temporarily overshadowed the ongoing hostilities between the northern army and southern-allied forces in the northern state of South Kordofan and other violence along the north-south border. The south and north have yet to agree on a demarcated border, and the issue of oil remains contentious. The south has most of the oil but it must move it through the north's pipes.
Dozens of world leaders joined a crowd tens of thousands strong in Juba on Saturday. The American delegation was led by Susan Rice, who told The Associated Press in a phone interview on Sunday that the U.S. government remains "focused on the urgency of resolving" the outstanding north-south issues.
"We feel that until they are resolved, there's a real risk of the process to date beginning to unravel," she said.
Rice said that the U.S. government would remain "very actively involved" in supporting negotiations between Khartoum and Juba. U.S. officials say they hope the talks will restart in the next week through a process led by an African Union panel.
"As wonderful a day as yesterday (Saturday) was ... we are mindful that even as those presidents pledge a commitment to peaceful and cooperative relations, that these issues are such that in the absence of resolution there is a risk of things beginning to disintegrate," she added.
Sudan President Omar al-Bashir, who is wanted for war crimes for his role in the conflict in Sudan's western region of Darfur, attended Saturday's ceremony and appealed for the two nations to work to "overcome the bitterness of the past."
Rice dismissed the possibility of U.S. military intervention in South Kordofan, where northern aerial bombardments have driven tens of thousands of black Africans from the Nuba ethnic group into caves for protection from the raids. She noted that the U.S. has not been involved militarily in Sudan and she doesn't foresee that changing in the near future.
She said that given the great urgency of the ongoing crisis, the U.S. is working hard to continue to "engage diplomatically to try to broker (a) cessation" of hostilities.
Southern Sudan voted in a January referendum to break away from the north as part of a north-south peace deal that ended the decades-long civil war in 2005. But the future of the 4,000-square-mile (10,500-square-kilometer) Abyei region, which lies near the north-south border, is still in flux.
South Sudan is expected to become the 193rd country recognized by the United Nations next week and the 54th U.N. member state in Africa.
At 0000  Saturday (2100  Friday), the Republic of South Sudan achieved independent recognition, becoming the newest country on the planet. The parliament speaker for the new country recited a formal independence declaration. After independence was declared, the South Sudanese flag was lifted for all to see, with  secretary general Pagan Amum stating: "Today we shall raise the flag of South Sudan to join the nations of the world". 

Thousands of jubilant people celebrated in the new country's capital Juba. They danced in the streets, sang songs and waved flags.  Churches rang their bells at midnight as independence arrived. People crowded to the official ceremonial site, held at the  of  , leader of the rebellion who died several months after the peace deal was signed with Sudan, ending the bloody conflict. Many of the celebrants spoke emotionally of their family members who died in the long struggle with Sudan.

George Garang, an English teacher, said he lost his father, grandfather and eleven brothers. "My whole body feels happy," he said. Valentino Achak Deng, who was a refugee during the war, said: "Really in my heart what makes me happiest is that from today, when people ask me where I am from, I do not have to say Sudan."

 has assumed the role as president of South Sudan. Kiir swore to pledge true alliance and faithfulness to South Sudan. In a speech, Kiir declared amnesty for any who have taken up arms against Sudan.

Kiir insisted that martyrs for the cause of the new country did not die in vain, although South Sudan waited 56 years to be free. The southern Sudanese had agitated for more rights, even before Sudan became free from its British colonizers in 1956. Sudan was divided into three separate demographic groups, with the southern part of the country home to Christians and animists and the northern part dominated by Arab populations and those of Muslim faith. Kiir said to people of , Darfur,  and , who remain part of Sudan, that "we have not forgotten you. When you cry, we cry. When you bleed, we bleed. I pledge to you today that we will find a just peace for all."

Amongst those attending the event were Ban Ki-moon, the current  and , the current president of Sudan. The latter was the guest of honour, despite the fact that the  has a warrant out for his arrest based on offences of  and  in the Darfur region.

"We congratulate our brothers in the south for the establishment of their new state," al-Bashir said at the event. "We share their joy and celebration. The will of the people of the south has to be respected."

Two million individuals died in the  between the two territories of Sudan and Southern Sudan and four million more exiled,  a war that was waged for decades. Control of south Sudan's oil rich reserves was the primary reason for the fighting. An  was signed in  2005, effectively bringing the war to an end, and Sudan became one of the first countries to recognise South Sudan. Under the regulations of the Comprehensive Peace Agreement, Sudan held an independence referendum. In excess of 99% of those participating in the vote agreed to the concept of independence for South Sudan. 

Meanwhile, the United Nations plans to make the independent state its 193rd recognised country and its 54th African U.N. member state. United States president Barack Obama formerly recognized the new nation on behalf of the US and acknowledged the enormous struggle of its people to achieve independence.

South Sudan remains a desperately poor country, with one in five of its inhabitants chronically hungry, only one third  having access to safe drinking water and with the world's highest rate of maternal death. The country lacks infrastructure such as roads and railways. It remains  torn by ethnic and tribal rivalries and many problems with the north remain unresolved, including the exact boundary line.  Important revenue for Sudan has come from the rich oilfields of the south, keeping the country afloat and essential now for both economies. A formula remains to be developed on how to split these revenues between the two areas.

U.S. ambassador to the U.N.  said today that the peace process between Sudan and North Sudan could come apart if issues  such as the division of the oil revenues and the border location are not solved soon.