At least three prisoners have been killed during a riot in the main prison in Ivory Coast's biggest city of Abidjan, officials say.One inmate told the BBC the riot began after guards tried to move a prisoner they suspected of planning to escape.The BBC's Tamasin Ford says the prison is now quiet.The jail holds some of Ivory Coast's most violent prisoners as well as some supporters of former President Laurent Gbagbo.The prisoner, who did not want to be named, told BBC Afrique that cells had been set on fire before guards were sent in to restore order.One guard was severely beaten and "left for dead" after being overpowered, before reinforcements used live bullets, he said."It was a mutiny at the prison that was quickly put down in order to keep it from getting out of control. There were three deaths," Lieutenant Moussa Doumbia, head of the unit sent to put down the uprising, told Reuters news agency.Soldiers with rocket-propelled grenades were deployed outside the prison, our correspondent adds.Another source inside the jail told the BBC that inmates had accepted a full search of their cells in return for food and water.Mr Gbagbo refused to accept defeat in 2010 elections and was ousted the following year with the help of French and UN forces backing President Alassane Ouattara."We fear the authorities will use this against pro-Gbagbo detainees," the prisoner told the BBC.Mr Gbagbo is currently facing trial at the International Criminal Court at The Hague.