By Ishbel Matheson BBC, Bujumbura

More than 100 African Union peacekeepers have arrived in the Burundian capital, Bujumbura - the first contingent of a force supposed to be 3,000 strong.

South African troops are already protecting politicians in Burundi

The peacekeepers' mandate is to help enforce a ceasefire signed between some Burundi rebels and the government last year.

However over the past few months, the ceasefire has been widely flouted.

Some 300,000 people have been killed in the 10-year war between the Hutu rebels and the Tutsi-led army in Burundi.

The deployment of this small contingent of South African peacekeepers is mainly symbolic, a gesture by the African Union that it is backing Burundi through a crucial transition time.

Anxious time

On Wednesday, the Burundian President, Pierre Buyoya - a Tutsi - will stand down and his Hutu vice president, Domitien Ndayizeye, will take over.

Ndayizeye (l) succeeds Buyoya (r) on Wednesday

It is an anxious time as Burundians wonder whether the new president has a better chance of striking a peace deal with the Hutu rebels, bringing to an end the bitter civil war.

Eventually, peacekeepers from Ethiopia, South Africa and Mozambique are supposed to be deployed in Burundi.

But it is not clear at the moment what their job entails.

Theoretically they are mandated to help enforce a ceasefire between one of the main rebel groups and the government army.

But that ceasefire has been repeatedly violated with Bujumbura, coming under rebel attack in the past few days.