The Sudanese government is denying claims that it has launched a massive offensive in southern Sudan. The government blames the fighting on tribal militias.
Rebels of the Sudan People's Liberation Army (SPLA) say that 1,000 people have been killed and thousands of others displaced by the offensive, which began Friday in the Western Upper Nile region of Sudan.
Mohamed Dirdeiry, a senior official at the Sudanese embassy in Nairobi, said the government is not involved in what he describes as skirmishes.
"There is no offensive from the government. This is completely the figment of someone's imagination," he said. "What is happening is that there are some skirmishes here and there, mainly between tribal militias, tribal clans, who want to position themselves better before peace. The government army is not at all involved in any fighting right now."
Mr. Dirdeiry said the government of Sudan does not control the militias, which "have their own agendas."
Dan Eiffe is with a humanitarian agency called Norwegian People's Aid. He said his agency has workers in the area of the fighting and their account of what is happening directly contradicts Mr. Dirdeiry's version of events.
Mr. Eiffe said the militias could not be doing what they are doing if they did not have the support of the government in Khartoum.
"They have launched a major offensive. They would not have the capacity to do that. They are supported by helicopter gunships and they have taken over a large area of Western Upper Nile in Mayam County," he noted. "We are working in that area and we have people up there. And we have people coming out of the field who can verify what I am saying. We have a health center, which received many, many wounded people on Saturday and Sunday from that area."
The government of Sudan and the SPLA have been fighting since 1983. The rebels, who are based in the south of the country, want greater autonomy from the Islamic military regime in the north.
Last week, there was a major breakthrough in peace talks when the government agreed to let the south hold a referendum on self-determination, following a six-year interim period.
Observers believe both sides are eager to shore up their positions ahead of cease-fire talks, due to begin in Kenya in mid-August. The area of Western Upper Nile is particularly sensitive because it is an area rich in oil fields.