The summit, which is hosted by Mauritania for the first time, is being held amid tight security measures.
Security in the Sahel region and the Western Sahara conflict between Morocco and the Polisario Front figure high on the agenda of the African meeting.
Talks are also expected to focus on the deteriorating security situation in the Central African Republic, illegal immigration and coordination on fighting organized crime.
Delegations of 22 African countries are led by heads of state, including Sudan, Nigeria, Mali, South Africa and Senegal. Several other countries are represented by heads of government, including Egypt, Algeria, Somalia and Cameroon.
