Sudan's President Omar Hassan al-Bashir and his Chadian counterpart Idriss Deby signed a peace agreement on Thursday meant to end cross-border rebel attacks in a region which includes Sudan's war-torn Darfur.

The signing, witnessed by U.N. Secretary-General Ban Ki-moon and Senegal's President Abdoulaye Wade, followed talks in Dakar meant to revive a string of bilateral pacts that have failed to end fighting on both sides of the Chad-Sudan border.

"We decide solemnly before our peers and representatives of the international community to reconcile our two countries, to normalise our relations and to give ourselves the means to contribute to the peace and stability of our two nations and of the region," a copy of the agreement seen by Reuters said.

The two countries agreed to the formation of a "contact group" made of foreign ministers from a handful of African states which would meet monthly to ensure the deal -- known as the Dakar agreement -- was implemented in good faith.

Foreign diplomats say Chadian rebels have regularly used the Darfur frontier region as a base from which to launch incursions into Chad. Sudan has in turn repeatedly accused Chad's government of backing Darfuri rebel groups.

Wade, who has sought a mediation role in several African conflicts, drafted the accord signed by Deby and Bashir in the hope it could help end the hostility.

Senegal is currently hosting a two-day summit of the 57-nation Organisation of the Islamic Conference (OIC), a diverse body grouping a quarter of the world's population spread across Africa, Asia and the Middle East.