US President Barack Obama has begun talks with Ethiopia's Prime Minister Hailemariam Desalegn on the second leg of his African tour, ABC news reported.

They discussed trade and security and Obam called for greater human rights and warned of the dangers of corruption.

Obama, who arrived late on Sunday in Ethiopia, will become the first US president to address the 54-member African Union at its headquarters.

Talks with African leaders, the AU commission chairperson and Sudanese foreign minister will also cover imposing an arms embargo on South Sudan to force it put an en end to the 19-month-long civil war.