Oil may be the key prize in Sudan's long civil war. Both the government in Khartoum and rebels fighting for autonomy in the south want control of the country's rich oil fields. The human cost of this war is huge.

Sudan produces about 250-thousand barrels of oil a day in a 300-million-dollar a year business. And the potential is even greater. Sudan has proven reserves of about 700-million-barrels, with another two-billion-barrels estimated.

And that, analysts say, is the big prize in the country's long civil war.

The current phase of the conflict has continued for 19-years. And the human toll is immense, an estimated one-and-one-half-million people have died in the fighting and accompanying famine. About four-million people have been displaced.

One of them is 57-year-old Apet Mal, who says she is tired of running from bombs and attacks by troops loyal to Sudan's government, known as the Popular Defense Forces.

Ms. Mal spoke to V-O-A in her native language, Dinka, and an interpreter explained why she came to the southwestern Bahr el Ghazal area for refuge:

"She is saying that she does not have any shelter. She was always displaced because there was always insecurity in that place. Sometimes, the P-D-F comes and they are displaced. She says now two of her children are killed because of running. So they move from one place to another."

Both the Sudanese government and the rebels blame the other for the war's terrible human toll.

The rebel Sudan Peoples' Liberation Army says government forces and government-backed militias often attack in the oil-rich area to clear it of people in order to secure existing or potential oilfields.

Philip Aguir is with the S-P-L-A's relief arm.

He says, "Khartoum is trying to create a buffer zone between the oil companies that are digging oil and the S-P-L-A, and this is by pushing the population very far away. We now have more than 300-thousand among the civil population that is on the move in the Western Upper Nile and they are not stable since two-years ago."

The rebels also say that the government uses its oil revenue to buy more sophisticated weapons to increase the intensity of fighting.

In Khartoum, the government says it is the S-P-L-A that is to blame for fighting in the oil region and for the loss of life. The head of Sudan's humanitarian aid commission, Salaf al Din Saleh, says the government is urging people to settle in the area and is expanding the services it can provide them.

He says, "From the oil revenues, the government has paved roads. It has made electricity, water facilities, schools, clinics; and we are inviting the people to come to the area. People have come to other places within the oil exploration area, and we are welcoming people to come there. All these towns are in the oil production areas: Bentiu, Mayom, Rapkona, and they are staying there."

But relief agencies operating in southern Sudan, like the London-based Christian Aid, say the Sudanese government's "scorched earth" policy is well documented. The agencies say that since oil pumping began three-years ago, homesteads have been destroyed and the land cleared of people in order to increase oil exploration and production by foreign firms from China, Malaysia, France, and Canada.

They say oil companies build roads and airstrips, and government troops use them to tighten their control of the region.

But Christian Aid also says rebel forces attack oil facilities and areas under government control. The group's spokeswoman, Judith Melby, says the latest fighting only reinforces the need for international monitors in the area to ensure the protection of civilians.

She says, "Now, if we have some kind of cease-fire, some kind of peace process going on, the whole issue of oil sharing must be looked at carefully. Oil is a natural resource. It is tremendously interesting to both sides, and both sides are interested in having the greater share, if you like, of the oil potential of Sudan."

A key architect for peace in Sudan, U-S special envoy John Danforth, agrees. He says there can be no enduring peace settlement in southern Sudan unless oil is shared.

Some progress is being made. The Sudanese government recently agreed to let the south hold a referendum on self-determination after a six-year interim period.

But that leaves the oil question, and the matter of power-sharing, among issues to be resolved. Further peace talks are scheduled in Kenya later this month.