The Sudanese government and the rebel Sudan People's Liberation Army (SPLA) will sign a deal this weekend clearing the last major hurdles to a settlement of their 20-year civil war, a senior US official and a rebel spokesman said on Wednesday.

The announcement comes a day after Washington piled pressure on the rival sides, saying their marathon talks hosted by Kenya had come to a "make-or-break" point.

"The good news is that they have made fairly decent progress on some of the last remaining issues, and both parties have assured me that they can complete the discussions by this weekend -- Saturday or Sunday. I believe they can finish this," Acting US Assistant Secretary of State for African Affairs Charles Snyder told journalists in Nairobi.

Snyder was talking after meeting Sudan Vice President Ali Osman Taha and SPLA leader John Garang, who have been engaged in the face-to-face talks since September of last year in Naivasha, northwest of Nairobi.

An SPLA spokesman, Yasser Arman, said in Cairo that a deal would be inked by Saturday, but added that some technical details would remain before a final settlement was reached.

On Tuesday chief mediator Lazaro Sumbeiywo announced a major breakthrough, when the two sides overcame disagreement on major remaining issues of power-sharing and the administration of three disputed regions.

Specifics of the expected deal were not immediately available, but they concern Abyei, Nuba Mountains and Southern Blue Nile where, though they are not strictly part of southern Sudan, the SPLA claims to represent the people.

The war, which along with famine and disease killed at least 1.5 million people and displaced over four million, has pitted the oil-rich state's wealthier Arabised Muslim north and its poorer south, where most are Christian or practice traditional Animist religions.

Snyder, repeating a view expressed in Washington earlier this week, suggested it was time for talks over the long-running civil war to end.

"There has been a growing concern that these parties are dragging too long and both sides know very well what the answers are, what range within which answers can be found. They have been talking for over six months, and very much on the same issues," he said.

According to the US official, the two sides have finalised about 90 percent of the sticking points and will have reached that by the weekend "a framework or principle agreement. A comprehensive agreement will be reached in a month or so." Snyder also condemned ongoing violence which is raging in Sudan's western Darfur region, where over 10,000 people are believed to have died and a million others displaced since February last year.

He said that "lack of political will in the face of what is happening in Darfur is not acceptable," but suggested that advances on the main Sudanese peace talks would be "very encouraging for the process in Darfur".

Members of the Khartoum government and Darfur rebels on Wednesday resumed direct talks, while UN Secretary General Kofi Annan urged world leaders to intervene there in order to avoid any recurrence of atrocities similar to the genocide in Rwanda - Sapa-AFP.