The United States is calling Darfur rebel leaders to Nairobi this week for talks aimed at healing their deepening divisions and restarting negotiations to bring peace to the devastated region of western Sudan.

The US-sponsored conference is scheduled to take place on November 8 in the Kenyan capital.

Deputy Secretary of State Robert Zoellick will lead the American delegation in an attempt to quell a power struggle that has divided the Sudan Liberation Movement (SLM), the largest rebel force in Darfur.

Nairobi was chosen as the venue for this "important" meeting because it is viewed as "neutral ground," said Jendayi Frazer, the State Department's top official for Africa. One rebel leader declined to take part in talks last week in Darfur because of security concerns, Frazer told a US congressional panel.

"It's critical that the SLM come together," Frazer said. Without rebel unity, she added, the Darfur peace talks "won't go anywhere."

Splits in the rebels' ranks are mainly to blame for the stalemate in the peace negotiations hosted by Nigeria, added Congressman Chris Smith, chairman of the congressional panel that invited Frazer to discuss Bush administration policy toward Sudan.

The government of Sudan also bears responsibility for the impasse, Smith said. Libya and Eritrea are to blame as well, he added, because of their support for the Darfur rebels.

Smith's and Frazer's comments are indicative of growing US frustration with rebel forces that have been fighting for nearly three years to win greater autonomy for the Darfur region.

It is estimated that up to 300,000 lives have been lost as a result of the conflict.

Until recently, US officials seldom criticised the Darfur rebels, instead assigning fault almost exclusively to the Sudan government and to local Arab militias known as Janjaweed.

The Bush administration has in fact charged on several occasions that these forces are carrying out genocide against the mainly black African population of Darfur. And last week the White House renewed economic sanctions against the government of Sudan on the grounds that it is continuing to sponsor terrorism.

At the same time, the United States has consistently kept its distance from the Darfur rebels, whom Washington views as politically problematic due to the Islamist orientation of some groups. This tacit disapproval has given way to explicit criticism in the past month following rebel attacks on the African Union peacekeepers deployed in Darfur.

In her remarks last week to Congress, Assistant Secretary of State Frazer deplored "the current spike of violence, caused by banditry, actions initiated by rebel movements, and actions by government forces, and continued marauding by the Janjaweed militia."

Frazer also suggested that elements within the Sudan military are continuing to provide intelligence and perhaps weapons to the Kony forces that have been terrorising northern Uganda.

Joseph Kony's Lord's Resistance Army (LRA) has also started to attack the southern Sudan guerrilla army that recently concluded a peace agreement with the government of Sudan, Frazer said. She called this "a very, very dangerous situation."

Frazer told the congressional panel that "what we fear is that there may be elements within the military that continues to provide information to the LRA, and maybe even arms. They may not represent government of Sudan policy. That's a question that's still out there. But there's certainly some type of assistance, we believe, continuing with the LRA."