The Colombian government and the Revolutionary Armed Forces of Colombia (FARC) rebel group took a final step toward peace in their decades-long conflict Thursday, signing a definitive cease-fire agreement at a ceremony in Havana.Colombian chief negotiator Humberto de la Calle and guerrilla leader Luciano Arango signed the agreement at a ceremony in Havana before Colombian President Juan Manuel Santos and FARC commander Rodrigo "Timochenko" Londono, with UN Secretary-General Ban Ki-Moon and a host of regional leaders from Cuba, Mexico, Venezuela, Chile and El Salvador in attendance.The cease-fire is years in the making, a final step in peace negotiations launched in 2012. In the agreement, both sides agreed to ban arms in the exercise of politics - a historic step for a country embroiled in civil war since the 1960s.FARC agreed to use non-violent means to work for its political goals, and the government promised to protect the disarmed rebels - in contrast to the 1980s, when thousands of members of the FARC's nascent Patriotic Union political party were slain by right-wing paramilitaries.Negotiators have already agreed on transitional justice programmes, aid to victims of the conflict, joint action against organized crime, agricultural development programmes in rebel territories and political participation for former guerrillas.Eleven months ago, FARC announced a unilateral ceasefire. Although Colombia suspended its air campaign against the guerrillas, the government had until now had refused to end a ground offensive.Government and guerrillas laid out a 180-day road map at the end of which FARC will have disarmed. The disarmament is to be verified by a working group composed of government and FARC representatives and United Nations observers.Colombia's decades-long civil war has left more than 220,000 people dead and driven millions from their homes. Santos has said a final peace treaty could be signed next month.