A military court in Ivory Coast on Thursday sentenced three soldiers loyal to ex-president Laurent Gbagbo to life in prison over the 2002 murder of a former junta leader.

General Robert Guei was shot dead on September 19, 2002, during a failed coup against Gbagbo's regime. His wife, several members of his family and his personal guards were killed that same day.

Guei had led a military junta that ruled the west African nation from December 1999 to October 2000, when Gbagbo defeated him at the polls.

Following a trial that last nearly a month, the court-martial found ex-security chief Anselme Seka Yapo guilty of murder, while Gbagbo's former Republican Guard commander Brunot Dogbo Ble as well as sergeant Daleba Sery were ruled to have acted as accomplices.

Of the 19 defendants on trial over the murder, six were sentenced to 10 years in prison. The others were acquitted.

During the trial, prosecutors accused Seka Yapo of firing the fatal shot.

Lawyers for the defence have said they intend to appeal the verdict, citing a lack of evidence of their clients' guilt.

"I am disappointed but not discouraged," said lawyer Modeste Abie. "We believe that our clients do not deserve life terms."

Seka Yapo was last year already sentenced to 20 years in prison for murder committed during the country's post-election crisis in 2010-2011.

Dogbo Ble was sentenced in 2012 to 15 years in jail for complicity in the murder of a retired officer, and last year to another 20 years for his role in the 2010-2011 violence.

Some 3,000 people were killed after the disputed presidential vote in late 2010, when Gbagbo refused to relinquish power after being narrowly defeated in his bid for re-election.

He is currently on trial at the International Criminal Court in The Hague for crimes against humanity over the violence.