Cease-fire violations are on the rise in Sudan's bloodied Darfur (search) region and the fighting is "poisoning" peace talks, where government and rebel negotiators met Monday for the first time, officials said.

Thirteen violations of a cease-fire agreement were confirmed in September and 54 were documented between October and mid-December, said Assane Ba, a spokesman for the African Union (search), which is mediating the talks.

"That means the violations are growing" in the western Sudan region, where the crisis has left tens of thousands dead and nearly 2 million homeless, Ba told reporters at the site of the talks in Nigeria's capital, Abuja.

"This is poisoning the atmosphere and we can't have meaningful negotiations in this situation," Ba said.

The fourth round of Darfur peace talks, which officially got under way Saturday, saw the first face-to-face working meeting Monday between Sudan's government and Darfur rebel negotiators.

Mediators confronted the warring parties with their cease-fire report, but only the government side responded before the meeting adjourned after a power outage plunged the hall into darkness, Ba said of the closed-door conference.

Government negotiators acknowledged its role in the skirmishes, saying they were only trying to clear Darfur's roads for humanitarian aid shipments, Ba said.

Previous peace negotiations have failed to stop nearly two years of fighting. AU officials said attacks continued last week.

Representatives from Darfur's two main rebel groups and Sudan's government are attending the talks, which are expected to focus on reviewing past interim agreements, with power- and wealth-sharing and disarmament among the final goals for peace.

Two newer, smaller insurgent groups aren't represented at the talks in Nigeria, a regional economic and military powerhouse that is the current head of the 52-nation African Union.

Earlier talks produced a Nov. 9 accord on humanitarian access to the estimated 1.8 million war-displaced in Darfur and in neighboring Chad, bringing new pledges of an end to hostilities — promises that were immediately violated.

Disease and famine have killed 70,000 in Darfur since March, the World Health Organization (search) says. There is no official reckoning of the overall toll of the war, which was sparked in February 2003 when two non-Arab African rebel groups took up arms to fight for more power and resources.

The Sudanese government responded by backing an Arab militia known as the Janjaweed (search), which is accused of targeting civilians in a campaign of murder, rape and arson.

The United States has accused Sudan's government of failing to take sufficient steps to rein in the Janjaweed militia, who are alleged to have committed genocide in Darfur.

Additionally, a promised 3,000-member AU peace deployment for Darfur has so far managed to put only about 800 soldiers and 100 observers in the field. The United Nations calls the situation in Darfur the world's gravest humanitarian crisis.