At an official ceremony, the group registered as a legal political entity known as the National Council for the Defence of Democracy (CNDD), which had until now been the political wing of the FDD.

"Today we begin the political struggle," party leader Pierre Nkurunziza told reporters, stressing, however, the transformation did not necessarily mean the FDD had formally renounced war.

The FDD and Burundi's government reached a ceasefire in November 2003 after which the ex-rebels joined the government and won representation in parliament.

But the group had not formally registered as a political party until now.

Monday's move followed the signing into law late last year by President Domitien Ndayizeye of two laws that created a new army and police force that include former rebel fighters and cantonment zones.

Those laws are an extension of the Arusha accord, a power-sharing deal signed in 2000 with the aim of halting Burundi's civil war, which began in 1993, and has since claimed more than 300,000 lives.

Since the cease-fire between the FDD and the government, only one of seven rebel groups, the National Liberation Forces (FNL), is still fighting.

The country is in a transitional phase of government which is due to end in April with presidential elections, but plans for a referendum on a new constitution have already been pushed back three times.

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