The Sudanese government and the country's southern rebels on Wednesday signed a key agreement on how to share the country's oil wealth, bringing the two sides one step closer to ending their two decades-long civil war.

Hailing the agreement as a major achievement, the leader of the rebel group, Sudan People's Liberation Army, John Garang, and his Sudanese government counterpart, Vice President Ali Osman Taha, agreed Wednesday to share the country's wealth at a signing ceremony in the Kenyan town of Naivasha.

The pact stipulates that the rebels equally split oil and other revenue from southern Sudan with Khartoum during a six-year transition period of autonomy from the government.

The interim period is due to go into effect once a comprehensive peace accord is reached.

Africa's longest-running war began in 1983 when the mainly Christian and animist southern rebels took up arms against the predominantly Arab Muslim government in Khartoum. The rebels have been demanding greater equality and autonomy in the south ever since.

The struggle for control of Sudan's vast oil reserves, which are mainly located in the south, became fierce after Sudan became an oil exporter in 1999. Rebels and international human rights groups have long accused the government of brutally forcing tens of thousands of civilians to flee oil-rich areas in the south.

The country currently earns an estimated two billion dollars a year from its oil production of more than 250-thousand barrels per day. Some experts believe that output could increase to 450-thousand barrels in the next two years, provided the country can end the war and attract enough investment from major Western energy companies.

But the two toughest issues of the peace process remain unresolved -- how to share power and the status of three disputed regions in central Sudan.

Last month, disagreements over details of those issues caused the warring parties to miss their self-imposed end-of-year deadline to reach a comprehensive peace accord.