Now, international mediators and rights groups are calling for stronger efforts to settle the eight-year Darfur conflict, fearing that the expected breakaway of the south may push Khartoum's leaders to clamp down harder on dissent and place stricter limits on an international role in Darfur and other areas that remain under its direct control.
Human Rights Watch and other groups say violence was already increasing in the vast arid region in the lead-up to the southern referendum held earlier this month. At the same time, government restrictions are making it harder to obtain information on conditions there, they say.
On Friday there were reports of new clashes between the military and rebels in Darfur, leaving 21 dead.
As many as 300,000 people have died as a result of the fighting in Darfur _ a vast region outside the secession-seeking south _ between forces from the Arab-led central government and rebel factions whose demands include greater control over natural resources. At least 2.7 million people have been displaced inside Darfur and in neighboring Chad.
The roots of the breakaway movement in the south are similar, but it's also fed by a religious split between the Muslim-dominated north and the heavily Christian south.
The referendum for southern independence was part of a 2005 peace deal that ended more than two decades of civil war. Preliminary results show overwhelming support to create the world's newest nation.
American officials visited Darfur during the referendum to send a message that the region will not be forgotten.
U.S. Senator John Kerry reminded Sudanese officials that prospects for improved relations with the U.S. hinge on progress in Darfur. He also urged greater international efforts to reach a resolution in Darfur after more than two years of talks in Qatar have failed to reach a comprehensive peace deal.
Mediators from the African Union echoed Kerry's appeal.
Roger Middleton, a Sudan expert with the London-based Chatham House, said the impact of the referendum on Darfur is still far from clear.
"There are two possibilities. One of them is that the loss of southern Sudan and the loss of that big obstacle frees up Khartoum to really focus on winning a war _ a political war, at least _ in Darfur and that gives them the ability and time and the money to focus on that," he said.
The other possibility is that the Darfur rebels could take inspiration from the south "and perhaps even potentially (see) an ally in the new southern independent state," said Middleton.
In advance of the referendum, violence flared between government forces and the array of Darfur rebel groups, which pledged to unite. U.N. officials said as many as 40,000 people were displaced by the December fighting.
The government walked out of peace talks held in Qatar's capital, Doha, after failing to reach a cease-fire agreement. And a rebel leader who had signed a peace deal with the government in 2006 fled to southern Sudan, prompting the government to declare him a public enemy.
The "defection" of Minni Minawi, who was appointed a presidential adviser after signing the peace deal, has raised alarms about the potential of proxy wars between north and south.
"We don't think that it is in the best interest of the new state of south Sudan to be a sanctuary" for rebel groups, the head of the U.N.-African Union peacekeeping mission, Ibrahim Gambari, told The Associated Press.
He has held recent talks with the U.N. mission in Sudan over tightening security cooperation along the 286-mile (460-kilometer) border between Darfur and breakaway south Sudan. U.S. officials said President Barack Obama also raised the issue with the southern Sudan president, Salva Kiir, before the referendum.
But despite a public promise from Kiir to deny Darfur rebels a home in southern Sudan, Minawi is still in the south. He was quoted by Sudanese papers as saying there has been no progress in talks with Khartoum officials over his return.
Mediators say the Doha peace talks are not dead. Shuttle diplomacy between rebel groups and the government have already began and a small delegation from the main rebel faction, the Justice and Equality Movement, is currently in Qatar.
"Now with the referendum and maybe in July the separation, I think the attention of the international community will be focused ... to have a success story like with the north-south," Gambari said, adding that sanctions against rebel groups refusing to join the talks are also being considered.
There are fears, however, that Khartoum could move to limit access to Darfur and the rest of its territory to international groups, like those providing crucial humanitarian aid to the displaced.
The Small Arms Survey, a research project that monitors armed violence, said in a January report that the northern ruling party has made it clear "it would set the price of southern secession very high, and part of that price would be limitations on the international community's role in and access to the north." The report said mediators have expressed concern that a Darfur deal _ if reached _ may be impossible to "implement in the shrinking political space that is expected to follow the referendum." Government officials said they hope a peaceful settlement with the south would open the door to settle Darfur. Khaled Musa, Foreign Ministry spokesman, insisted armed revolt will get the rebels nowhere.
"When the government signed (the southern peace deal) it was not in its weakest political or military position. We had the upper hand," Musa said. "The only possible way to resolve Darfur is through political negotiations." But the rebel Justice and Equality movement accused government forces of capturing some of its senior military commanders this week. It also condemned government efforts to open dialogue with Darfur residents as an attempt to sideline the rebel groups.
A Sudanese army spokesman said clashes erupted between army forces and JEM fighters a week after the referendum, killing 21 people, including 13 rebel fighters.
"Our priority is to work within a united Sudan. But if the suffering and crimes continue without a resolution, all options are open," said Ahmed Hussein, a spokesman for the rebel group. "For now the focus is on working within a united Sudan and we don't demand a separation for the time being." 220913 jan 11GMT