United Nations secretary-general Ban Ki-Moon has called on Sudan and South Sudan to reach a comprehensive agreement at a summit of its leaders in Ethiopia.
Mr Ban said in a statement that Sudan president Omar al-Bashir and South Sudan President Salva Kiir must put aside differences over oil and borders at their summit in Addis Ababa and create "a new era of peace, co-operation and mutual development for the two countries and their people".
On Thursday, the Security Council called for an urgent agreement on a demilitarised border zone.
US ambassador to the UN Susan Rice has warned that Sudan's refusal to accept an African Union map demarcating the border with South Sudan could lead to the resumption of "outright conflict".
South Sudan won independence from Sudan last year.