Mahamat Said Abdel Kani pleaded not guilty to all charges on Monday at the International Criminal Court (ICC) as his long-awaited trial started at The Hague.

The former top-ranking rebel commander is accused of carrying out or ordering crimes against humanity and war crimes in the Central African Republic (CAR) in 2013.

"I plead not guilty on all situations, on all charges," he told the court.

The ICC is prosecuting him on seven counts of war crimes and crimes against humanity committed between April and August 2013 in Bangui against detainees accused of supporting former President François Bozizé.

According to the United Nations, before the crimes were committed, the Séléka militia advanced towards the capital, attacking police stations, occupying military bases, capturing towns and regional capitals, and targeting suspected supporters of President François Bozizé.

They seized Bangui in March 2013 and with forces numbering up to 20,000, looted homes while searching for sympathizers of Bozize, shot those fleeing in the back or killed others in their homes.

The ICC prosecutor has lined up a total of 43 witnesses in the trial.

Said's defence team however dispute the reliability of the evidence against him.