Ivorian soldiers (FRCI) patrol on July 22, 2012 in Duekoue
Ivory Coast opened began the trial of the massacre of over 800 people killed in the remote village of Duékoué located in the Western region of the country.
817 people were executed in one day, according to the Red Cross while the UN puts the figure at 300.
Among those availed for the trial is the former warlord Amade Ouremi nicknamed the Lord, arrested in 2013.
Oueremi was detained by the military in a village close to a national park, where he had been based for more than 20 years.
Ouremi together with his men is accused of assassinations, rapes, insurrections and other forms of atrocities.
He denied the charges but if found guilty, the former warlord might face a 20-year jail sentence.
Reports indicate that Ouremi began supporting anti-Gbagbo rebels as early as the year 2000.
Ouattara's government came under criticism for failure to arrest Ouremi.
