BUJUMBURA, Nov 23 (Reuters) - Burundi will appoint former Hutu rebels to four cabinet posts later on Sunday, including the key security ministry, a presidential spokesman said.

President Domitien Ndayizeye's inclusion of officials from the Forces for the Defence of Democracy (FDD) in his new cabinet is the clearest sign yet of political reconciliation following Burundi's decade-long civil war that has killed 300,000 people.

"Everything is ready. We are waiting for an official announcement by the president of the republic," said presidential spokesman Pancrace Cimpaye.

"Beside the ministry of state, the FDD was handed the ministry of interior and public security, the ministry of communication and ministry of public works." he added.

FDD spokesman Gelase Daniel Ndabirabe told Reuters by telephone that FDD officials were travelling to the capital Bujumbura to join the government and the joint ceasefire monitoring commission.

He declined to name the new ministers, saying only that: "I know our movement must have key posts in the government."

Ndayizeye and the FDD, led by Pierre Nkurunziza, agreed last month to share power to try to end the war.

Under the deal, the former rebels will account for 40 percent of the army and police, giving ethnic Hutus broader representation in the Tutsi-dominated army and government.

The FDD will also be represented by 15 members of parliament.

The army is still battling the Forces for the National Liberation (FNL) rebel group, which has refused to join the peace process and denounced the government's deal with the FDD.

Analysts say addition of FDD forces will give the army a better chance of defeating the FNL, who were given three months by regional leaders to join the peace process or be branded outcasts.