With UN Security Council ambassadors bearing witness, a Sudanese government official and a representative of the rebel Sudan People's Liberation Movement (SPLM) signed in Nairobi, Kenya, a document pledging to complete a final peace accord by the end of 2004.
The accord would effectively end conflict in the oil-producing south of Africa's biggest country.
"The parties declare their commitment to expeditiously complete negotiations ... so as to conclude and sign the comprehensive peace agreement no later than 31 December 2004," the memorandum on Friday said.
"The parties recommend themselves to finalise and conclude a comprehensive peace agreement in recognition that prompt completion of the peace process is essential for all the people of the Sudan as it will help in resolving all challenges facing the country."
Meeting in an extraordinary session in Nairobi, the UN Security Council also hailed a resolution it passed in the African country urging an end to the two-decade war in Sudan saying it would pave the way for peace as well as help resolve the crisis in western Darfur.
Garang is to be a vice-president
in the Sudanese government
"History will prove that this will not only provide a perfect conclusion to the settlement of the long-lasting question in the southern Sudan, it will also be conducive to the solution of the question of Darfur," said China's ambassador Wang Guangya.
It raises the prospect of massive development aid if a deal is struck, and suggests its signing would help to bring peace to other areas of Sudan, notably the western region of Darfur, where a separate conflict has spawned what the UN terms the world's worst humanitarian crisis.
The southern civil war has killed an estimated two million
people, mostly from famine and disease, since 1983 when Khartoum tried to imposed Islamic sharia (law) on the mainly animist south.
Oil and ideology have complicated the conflict, which is separate from the war in the western Darfur region that has also brought tremendous international pressure on Khartoum.
Six preliminary peace accords on power-sharing, integrating the military, and dividing oil revenues have been signed.
"We do not want peace given by others but a peace made possible by our independent will, a peace made possible by the Sudanese people"
spokesperson, Justice and Equality Movement, Sudan
According to the accord, SPLM leader John Garang is to be a vice-president in Khartoum, along with current First Vice-President Ali Usman Muhammad Taha.
Ahmad Hussain, spokesperson for the Sudan's Justice and Equality Movement (JEM) told Aljazeera: "There should have been pressure on Khartoum so our people in Darfur could have secured all their rights.
"We are for comprehensive peace and stability across Sudan," he said.
"We do not want peace given by others but a peace made possible by our independent will, a peace made possible by the Sudanese people," Hussain said.
It was clear from the opening session of the Security Council that sanctions would not be imposed on Sudan's government, the spokesman said, adding that sanctions would be imposed if Khartoum does not abide by its commitments.