Efforts to end conflict across Africa, especially in Mali, dominated the African Union summit opening on Sunday.
"Much still needs to be done to resolve ongoing, renewed, and new conflict situations in a number of countries," AU Commission chief Nkosazana Dlamini-Zuma said in her opening speech.
"We cannot overemphasise the need for peace and security – without peace and security no country or region can expect to achieve prosperity for all its citizens," she told the bi-annual summit in the Ethiopian capital.
The 20th ordinary summit, which continues on Monday, opened with a minute's silence in memory of the late Ethiopian prime minister Meles Zenawi and Ghanaian president John Atta Mills, who died last year.
The meeting is expected to focus on the war against Islamist militants in northern Mali, including the scaling-up of African troops to support the weak Malian army.
Mali's army, boosted by the recent French military intervention, is battling Islamist insurgents, who seized swathes of Mali's desert north following a coup last year.
Dlamini-Zuma told leaders that the AU "must remain firm on its stance of no unconstitutional change" of leadership and that it must boost its "capacity to defend democratically-elected governments".
Following a security meeting on Friday, the AU resolved to bolster the strength of the African-led force in Mali, or Afisma, and gave member states one week to commit troops to the mission.
"The force size will have to be significantly augmented," AU peace and security commissioner Ramtane Lamamra told reporters after the security meeting.
Lamamra said Afisma's strength should be increased "to better respond to the needs on the ground", but declined to give numbers.
The AU will also seek urgent "temporary" logistical support from the United Nations to enable the Afisma force to "speedily deploy and effectively implement its mandate", according to an AU statement.
The logistical support should include transportation, medicine and field hospitals.
Also high on the summit agenda is the slow progress between the rival leaders of Sudan and South Sudan to implement stalled oil, security and border deals.
South Sudan's president, Salva Kiir, and his northern counterpart Omar al-Bashir met on Friday for face-to-face talks ahead of the summit.
The two leaders signed a series of agreements in September that have yet to be rolled out. Kiir blamed the delay on Khartoum after meeting with Bashir.
Diplomats said leaders are also expected to discuss recent unrest in the eastern Democratic Republic of Congo, where M23 rebels took over the key town of Goma before pulling out. They have since agreed to negotiations with the Congolese government, but the talks have been dragging.
The AU summit, officially themed "Pan Africanism and African Renaissance", will kick off the 50th anniversary celebrations of the founding of the Organisation of African Unity, the predecessor to the AU.
African leaders are also set to select a new AU chair to replace the outgoing head, Benin's President Thomas Boni Yayi. This post rotates each year on a regional basis.
Ethiopia's Prime Minister Hailemariam Desalegn is slated to replace Yayi, according to Ethiopia's foreign ministry. – AFP