The dispute between Ethiopia and Eritrea is expected to dominate the annual OAU summit, which begins in Burkina Faso on Monday.
African heads of state have been arriving in the capital, Ouagadougou, during the day.
Foreign ministers already assembled there are scheduled to hold a final meeting to approve the agenda for the talks.
The summit will also examine continued instability in countries including Sierra Leone and Angola.
From the newsroom of the BBC World Service