Some African heads of state plan to push for a united continent during an African Union summit that begins Sunday in the Ghanaian capital of Accra.

The three-day summit agenda is almost entirely dedicated to the idea of a United States of Africa. Proponents of the plan argue that a united federation of African nations could exercise more influence and better address problems facing the world's poorest continent.

Although several countries support the idea of a united continent, some regional powers like South Africa favor a more gradual consolidation of regional economic groups.

Leaders at the summit will also discuss the conflicts in Darfur and Zimbabwe.

The idea of a united Africa was conceived four decades ago by Ghana's first president, Kwame Nkrumah.