By Ishbel Matheson BBC, Nairobi

The chief negotiator of the Sudan peace process has described talks in Kenya between rebel leader John Garang and the Sudanese vice president Ali Osman Taha as a make or break time.

Sudanese government and rebels urged to reach agreement

General Lazarus Sumbeiywo is the widely respected Kenyan negotiator who has been steering Sudan's warring sides along the rocky path to peace.

But he describes the summit in the Rift Valley town of Naivasha as "the end of the game".

Rebel leader John Garang and Sudanese Vice President Ali Osman Taha have to reach agreement.

If they do not, he predicts a new outbreak of war.

He said a failure would mean the two sides were simply not ready to settle for peace.

'Hopeful'

General Sumbeiywo would not be drawn on the prospects for a breakthrough, but he described the atmosphere in the talks as hopeful.

The issues under discussion are the most fundamental and the most difficult to solve.

They include power-sharing, wealth-sharing, especially of Sudan's oil resources and the composition of a national army during a transitional period.

Sudan's war between the mainly Christian south and the Islamic north has lasted two decades and led to the deaths of hundreds of thousands of ordinary civilians.

Previous peace deals have been signed, only to fall apart later.