(CNN) -- The leaders of Sudan and newly independent South Sudan inked a deal Thursday that will resume oil exports, but failed to address other key disputes between the recently divorced countries.
The African Union and the U.N. Security Council had initially given Sudan's President Omar Al Bashir and South Sudan's President Salva Kiir one day to come to an agreement on several issues that have threatened to spark an all-out war between the two nations.
The two leaders began talks Sunday in the Ethiopian capital of Addis Ababa.
In addition to restarting oil exports from South Sudan, the two presidents agreed on a demilitarized zone and principles of border demarcation. Yet they could not reach a deal on the status of Abyei, a disputed region claimed by both countries, which has been a contentious issue since the South declared independence on July 9 of last year.
Speaking at Thursday's signing ceremony, Kiir said the agreement marked a great day for the two nations but called for a swift resolution to the question of Abyei's future, for the sake of its people.
Al Bashir also welcomed the deal, saying it reflected a "desire to achieve peace and stability and the mutual benefit" of the two nations.
U.N. Secretary-General Ban Ki-moon praised both presidents for "demonstrating the statesmanship that made a comprehensive agreement possible, and for having once again chosen peace over war."
Under the agreement, South Sudan will resume oil exports to Sudan, which controls the infrastructure through which the oil flows.
South Sudan shut off its oil supply in January, saying that Sudan was stealing oil revenue. The South got around 70% of the formerly united country's reserves when it became independent last year.
Both countries, especially South Sudan, have seen hyperinflation and a squeeze on incoming foreign currency, which has hurt their economies.
The deal also set up a demilitarized zone along the two countries' border where the militaries of Sudan and South Sudan and other armed groups are not allowed.
"This agreement breaks new ground in support of the international vision of two viable states at peace with each other," President Obama said in a statement Thursday. The United States is prepared to work with both countries to resolve the outstanding issues, he added.
The High Representative of the European Union for Foreign Affairs, Catherine Ashton, also praised the deal, saying the security agreements will contribute to stabilizing the border area.
The agreement did not address the status of disputed areas along the border and the fate of Abyei, critical security issues that must be resolved if the two countries are to have lasting peace. Those issues may be addressed in upcoming talks, according to South Sudan's spokesman Atif Kiir.
"For the border issues we had agreed that we are going to continue our talks and we are hopeful to reach an agreement for the peace and security of the two countries, for the peace of the two regions and for the international community," the spokesman said late Wednesday.
Under a 2005 peace agreement that ended Sudan's two-decade civil war, Abyei residents were to take part in a referendum on whether to join the South or remain a special administrative region within Sudan.
The vote was to take place in January 2011, at the same time as the referendum that led to South Sudan's secession. But disputes over who was eligible to vote prevented the referendum from going forward in Abyei.
Sudan and South Sudan have been under increasing pressure from the African Union and Security Council to resolve the matter peacefully.
In April, Sudan and South Sudan slipped close to all-out war with a series of tit-for-tat air raids and ground attacks that prompted the African Union and Security Council to push the two sides to act.
The Security Council had given the sides until Sunday to come up with a deal or face sanctions, but the negotiators said that deadline had been informally extended until the end of the talks.