Allegations that Sudan's Muslim-dominated government has short-changed its mainly Christian rivals in the south of up to $600 million in oil revenues could threaten a 2005 peace treaty that ended two decades of civil war.

The Britain-based Global Witness, which campaigns against conflict and corruption, claimed in a report published Monday that its findings raise "serious doubts about whether the revenues are being shared fairly."

Most of Sudan's oil production of some 500,000 barrels a day is in the south. Revenue was supposed to be shared under the 2005 treaty, with the south getting half the state revenues for oil drilled on its territory.

But Global Witness said there was a wide discrepancy -- 9 percent to 26 percent -- between government and oil company production estimates for the south in 2005-2007. There was no discrepancy in the figures for northern output.

On the basis of a 10 percent shortfall in its oil revenue, Global Witness calculated that "the south would be owed more than $600 million."

There was no comment from the finance and energy ministries. But the allegations against a regime widely criticized by the West will heighten tension as the country moves toward parliamentary elections scheduled for April 2010 and a referendum on southern independence in 2011.

Nearly 2 million civilians perished in the civil war, mostly from disease, famine and other war-related causes, the highest civilian death toll from any conflict since World War II. Another 4 million southerners were displaced.

The bombshell allegations and the possibility of renewed civil war came as the commander of United Nations and African Union peacekeeping forces in western Sudan declared that Sudan's other war, the six-year conflict in the Darfur region, was more or less over.

"As of today, I would not say there's war going on in Darfur," Gen. Martin Lowther Agwai, a Nigerian who heads the UNAMID peacekeepers, told reporters in Khartoum Wednesday. His two-year tour with UNAMID expired Thursday.

The fighting in Darfur between pro-government militias and non-Arab rebels, who took up arms in 2003, has largely degenerated into banditry, he said.

An estimated 300,000 people perished in the fighting, and 2.7 million were driven from their homes.

Agwai and Rodolphe Adada, former foreign minister of the Democratic Republic of Congo and UNAMID's outgoing civilian chief, reasoned that with the end of the massacres that marked the Darfur bloodletting and with death tolls dramatically lower, the war had been reduced to a low-intensity security problem.

"Militarily there's not much," Agwai said. "What you have now is … banditry, people trying to resolve issues over water and land at a local level. But real war as such, I think we're over that."

Still, he predicted that localized insecurity could continue for years without a peace settlement.

The upbeat comments by Agwai and Adada have been greeted with widespread criticism by many diplomats and relief organizations active in the region.

UNAMID has been widely branded as ineffectual, ill-conceived and poorly resourced since it was hastily put together in 2007.

"It's absolutely wrong," Colin Thomas-Jensen, a policy adviser with the anti-genocide project at the Center for American Progress think tank, said of the assessment by Agwai and Adada.

"The rebels have not been defeated and there is virtually no political process in play … It's two guys (Agwai and Adada) trying to save face and put a positive spin on what continues to be a disaster," he said.

"We have a continuing situation where the Darfur tragedy can erupt again at the drop of a hat."

This more somber assessment placed greater emphasis on the deteriorating political situation in Sudan as a whole and the prospect of renewed North-South civil war.

"If anything," Jane's Defense Weekly noted, "the Darfur analysts say that "while there is a lull in the fighting, the situation has grown more tortured and has intensified for a number of political reasons, not least of which is the re-emergence of the North-South divide as a flashpoint for conflict as Sudan moves gingerly toward elections and an eventual referendum in 2011 on secession for the oil-rich south.

"By declaring an end to the Darfur war, UNAMID may unwittingly be playing into the hands of the Sudanese government, helping to refocus international attention elsewhere and bolstering Khartoum's position in the face of a number of other rebellions and insurrections brewing elsewhere in the country," Jane's said.