African leaders are meeting in the Tanzanian city of Dar es Salaam in another attempt to resolve the conflict in Burundi.
Burundi's president faces calls to reduce Tutsi influence over the army
But a Hutu rebel group responsible for a major assault on the capital Bujumbura this month - in which 300 rebels and 15 government troops were killed - is not present at the talks.
The fighting between Hutus and Tutsis in Burundi has dragged on for 10 years, resulting in the deaths of hundreds of thousands of people.
Uganda President Yoweri Museveni and South African Deputy President Jacob Zuma - who brokered the talks - were seen entering the meeting on Sunday.
There were accompanied by Burundi's President Domitien Ndayizeye and leader of the Forces for the Defence of Democracy (FDD) Hutu group, Pierre Nkurunziza.
The FDD signed a ceasefire in December but has continued to fight across Burundi.
International force plea
Although Burundi's President Ndayizeye is also a Hutu, the FDD argues that the minority Tutsi still have too much control over the army.
There are expected to be calls at the talks for a more active regional peacekeeping force.
At the moment troops from South Africa and Mozambique have a limited mandate.
But according to the BBC's southern Africa correspondent Barnaby Philips, African governments will be unwilling to get more involved in what is seen as one of the continent's most intractable and tragic wars.
Meanwhile, AFP news agency reports that three local employees of Western non-governmental organisations who were kidnapped by FDD rebels were released on Friday.