By Ange Aboa ABIDJAN, May 17 (Reuters) - Militias which backed Ivory Coast's government in a 2002-2003 civil war have begun to disarm, participants said on Thursday, in a major success for a home-grown peace deal to reunite the West African country. The militiamen fought some of the fiercest battles of the brief conflict, in which rebels seized the north of the world's largest cocoa producer. The groups now control the town of Guiglo in the west where they are feared by locals. "We have already recovered a large quantity of weapons and we are continuing to ask the heads of the groups to bring us all they have," Bertin Kadet, a government defence and military adviser coordinating the disarmament, told Reuters by telephone. President Laurent Gbagbo will attend a ceremony in Guiglo on Saturday which Kadet said would mark the end of the process. It was not immediately clear if he would be joined by rebel leader and former enemy Guillaume Soro, whom Gbagbo named prime minister after they signed the peace deal in March which foresees reunification of the former French colony and elections by early next year. Militia disarmament is a key demand of the rebels, who say the groups must disband before they will hand in their own guns, but previous attempts failed when the combatants gave in only small numbers of guns or made demands for more disarmament cash. If successful now, their disbandment will be a major boon for the peace accord which has stirred a wave of optimism, following on from a string of foreign-imposed deals which foundered amid political squabbling. The sudden start to the militia disarmament, which defence adviser Kadet has overseen with the groups' leaders this week, contrasts with the fanfare of a failed attempt last August to disarm them with offers of money, job training and medical care. Denis Maho Glofiei, the most senior of the militia chiefs, said the combatants would still receive this support. "The reintegration of our combatants will be handled by the government's national disarmament programme," he said. "We have Kalashnikovs, pistols, very many weapons that we have gathered up here in Guiglo which we're going to hand over to the president and the prime minister," he told Reuters by telephone. Presidential spokesman Gervais Coulibaly-Delinpelna said in a statement on Thursday that Gbagbo considered the militias' decision to disarm a "patriotic initiative" which was important for a rapid return to peace.