Rival leaders of Sudan and South Sudan were scheduled to meet on Friday in Ethiopia to push for progress on stalled economic, oil and security deals to ease tensions between the former civil war foes.

The meeting between Sudanese President Omar al-Bashir and his Southern counterpart Salva Kiir was scheduled despite accusations from Juba on Thursday that Khartoum had launched aerial and ground attacks inside South Sudan.

The summit of the leaders, whose nations are both struggling with economic austerity cuts following Juba's halting of oil exports through Sudan's pipelines, is the latest of repeated rounds of African Union-mediated talks.

AU chief Nkosazana Dlamini-Zuma said she hoped the summit would "enable the two presidents to agree on the best means and ways of overcoming the challenges" of implementing deals inked in September.

Juba has accused Khartoum of a series of attacks - regularly dismissed by Sudan - ever since the two nations came close to all-out war in March and April last year, when their armies fought bitter battles over their disputed frontier.

But the fresh claims of clashes will add to tensions between the presidents, who were scheduled to meet on Friday for the first summit since they signed security and oil agreements three months ago, which have still not been implemented.

Along with a demilitarized border buffer zone, the September pacts allowed for a resumption of South Sudanese oil exports through Sudan. They also said border points would be reopened for general trade.

One of the objectives of the meeting was to "find solutions to the pending issues of the Abyei area", a region claimed by both Khartoum and Juba, Dlamini-Zuma added in a statement.

South Sudan said it remains committed to talks, despite the accusations of ground and air attacks in remote South Sudanese border regions on Wednesday, claims unconfirmed by United Nations peacekeepers.

South Sudan's Information Minister Barnaba Marial Benjamin said the summit was important because of the September agreements.

Sudan has made no comment on the reported clashes, but the SUNA news agency said that Bashir hoped "to speed up implementation of the cooperation agreements".

South Sudan separated from Sudan in July 2011 under a peace agreement that ended the 1983-2005 civil war, but key issues including the demarcation of hotly contested border zones remain unresolved.

Khartoum also accuses South Sudan of supporting rebels operating in Sudan, which has been a major obstacle to implementing the agreements.

The South, in turn, says Sudan backs insurgents in its territory.