The UN Security Council urged Sudan and South Sudan on Friday to step up efforts to end the rivalry that brought them to verge of war this year.
In a statement issued ahead of new talks between the two sides Tuesday, the 15-nation council welcomed the easing of tensions but expressed regret that they had missed an August 2 deadline to agree on a demilitarized border zone.
The Security Council said it "strongly urges" Sudan to accept an African Union-mediated map in order to establish the demilitarized zone and a monitoring system.
South Sudan has recognized the map, but the Security Council said the South should pull back its forces in the northern half of the proposed zone.
South Sudan, one of the world's poorest countries, split from Sudan in July last year. But the two sides have never agreed on a border and territorial disputes weigh on their tense relations.
The pair fought a two-decade civil war up to 2005 that left more than two million dead. Deadly clashes have erupted along their unmarked frontier this year, while tens of thousands of refugees have fled south from fighting in Sudan's border states of South Kordofan and Blue Nile.
The UN Security Council had given the two sides until August 2 to settle their differences or face sanctions.
The threat of "additional measures" was repeated in the statement but no new deadline has been set.
The rivals have agreed on a revenue-sharing deal - vital to both sides - from oil reserves that straddle the disputed frontier. But there is still a major dispute over the future of the Abyei territory claimed by both sides.
The Security Council said it backed African Union efforts to organize a summit to settle "all outstanding issues" and implement the oil accord.
African Union mediator Thabo Mbeki, a former South African president, has called for talks between the two governments in Addis Ababa next Tuesday.