Conflict in Central African Republic (CAR) and South Sudan have weighed heavy on African leaders during African Union (AU) talks, while the official theme is food security and agriculture.

State leaders gathered for a two-day summit of the continental bloc that started in Ethiopia on Thursday.

"The fact that these humanitarian tragedies are unfolding in the two countries at a time when we are talking about 'African renaissance' must be painful to all of us," Ethiopian Foreign Minister Tedros Adhanom said, speaking at a ministerial-level meeting on Monday.

There's a lot of concern at the moment that the AU isn't showing sufficient leadership in resolving these types of conflicts.

Phil Clark, politics lecturer at London's SOAS University,

But the 54-member bloc seems to be bogged down yet again trying to resolve conflict in member states.

"Unless we find (an) urgent solution, the situation in these two countries will have serious implications for peace and security in the region, and indeed the whole continent," he added.

Descending into caos

The unfolding humanitarian disaster in CAR, where a 5,300-strong AU force is deployed alongside 1,600 French soldiers, will be a key talking point.

CAR descended into chaos ten months ago after rebels overthrew the government, sparking sectarian violence that has uprooted a million people out of a population of 4.6 million.

On Saturday, after the official summit closes, African leaders and Western diplomats will also hold a pledging conference to raise cash for the African Union-led peacekeeping mission in the CAR, or MISCA.

"What we hope is strong support for MISCA, to enable it to implement its mandate more effectively," the director of the AU peace and security council, El-Ghassim Wane, told AFP.

The warring parties in neighbouring South Sudan signed a fragile ceasefire last week, but clashes between government and rebels continue, with thousands killed and over 800,000 forced from their homes in bloodshed that has now lasted for six weeks.

Peace talks led by the regional East African bloc IGAD adjourned after last week's ceasefire deal, with mediators calling for the AU to play a greater role in the peace process.

'Institutional weakness'

Heads of state will gather at the gleaming Chinese-built AU headquarters, which comes eight months after the bloc marked its 50th anniversary in May.

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Peter J. Pham, director of the Africa Centre at the Atlantic Council, said the AU's slow response to the crisis in CAR points to a deeper institutional weakness when it comes to rapidly evolving conflicts.

He was especially critical of AU plans for an on-call peacekeeping force.

"For all the talk -- we've had it for well over a decade -- about an African standby force, the fact is that when emergencies come up, it starts all over again," he said.

Phil Clark, politics lecturer at London's SOAS University, said the AU faces criticism in its response to crises, especially in South Sudan and CAR.

"There's a lot of concern at the moment that the AU isn't showing sufficient leadership in resolving these types of conflicts," he said.

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Leaders are also expected to focus on "Agenda 2063", a 50-year roadmap for the AU that has been a major pre-occupation for the head of the executive council, Nkosazana Dlamini-Zuma, as well as the controversial role of the International Criminal Court (ICC) on the continent. 

The one-year rotating chair of the AU, currently led by Ethiopia, has been replaced by Mauritania's Mohamed Ould Abdel Aziz, who became the north African country's president in 2009.

Source: Agencies