Former South African President Nelson Mandela has said he believes unrest will continue in Burundi unless the Tutsi minority relinquishes its monopoly on power.

"Fifteen percent of the population cannot go on monopolising political, economic and military power," Mr Mandela told a summit of African leaders in his role as chair of peace talks.

"As long as we have this situation, peace and stability cannot be achieved," he said.

Of Burundi's 6m inhabitants, 84% are Hutu.

Mr Mandela said that some of Burundi's leaders accepted the need for compromise, but that on occasions they thought with "their blood and not with their brains".

Leaders of the main Hutu rebel group have not turned up at the talks in Arusha, Tanzania, and it is unclear if they will attend.

Mr Mandela warned that the absence of key rebel groups was a serious drawback to hopes of ending the six-year war between the Tutsi-led army and rebel groups from the Hutu majority.

The radical wings of two Hutu groups, the Forces for the Defence of Democracy (FDD) and the National Liberation Forces (FNL), have not yet agreed to participate.

Foreign delegates

The president of Tanzania, Benjamin Mkapa, whose country has been flooded with tens of thousands of Burundian refugees, said that Burundi's leaders must know that political goodwill is not bottomless.

Presidents Paul Buyoya of Burundi, Joachim Chissano of Mozambique, Pasteur Bizimungu of Rwanda, Thabo Mbeki of South Africa and Yoweri Museveni of Uganda are attending the talks, as well as Kenyan Vice-President George Saitoti.

A plenary session of 18 Burundian delegations is due on Tuesday.

French Minister for Co-operation Charles Josselin, UK Foreign Office minister Peter Hain and Washington's special envoy for the Great Lakes, Howard Wolpe, were also scheduled to attend.

US President Bill Clinton will participate via video conferencing, addressing delegates on Tuesday.

Amnesties

The Arusha talks began in June 1998, bringing together 18 delegations from Burundi's government, parliament, opposition parties and some rebel groups.

The talks made little progress and did nothing to stop the bloodshed, which began in 1993 after the assassination of the country's first elected Hutu president, Melchior Ndadaye.

Most Burundians are peasant farmers who have suffered enormously.

More than a million people have been displaced by the war and more than 200,000 killed since 1993.

More than 345,000 Hutus remained confined in army-run camps and restricted from tending their land during the year's main planting season.

There are many issues to be hammered out in Arusha, including the questions of amnesties and how to integrate rebels into the army.