Havana, Cuba — (CNN) Colombia’s government and FARC rebels signed a ceasefire agreement Thursday that could end five decades of bloody conflict while negotiators work to reach a final peace deal.

The signing took place in Havana, where the two sides have been negotiating since November 2012 to end the civil war that has killed or displaced hundreds of thousands of people.

The agreement was signed by Colombian President Juan Manuel Santos and Timoleon “Timochenko” Jimenez, top commander for the FARC, the Spanish acronym for the Revolutionary Armed Forces of Colombia.

While a groundbreaking deal between the government and the FARC, the agreement does not include other guerrilla and paramilitary groups.

The longest-running insurgency in the Western Hemisphere, the FARC sought to emulate the Cuban revolution and install a Marxist-style government in Colombia.

Critics accuse the rebels of engaging in drug trafficking and kidnapping to finance their guerrilla war.

Billions of dollars in U.S. counterinsurgency aid has helped the Colombian government turn the tide against the FARC, which suffered as top commanders were killed and thousands of foot soldiers abandoned the insurgency.

At the beginning of peace talks, FARC rebels proposed a bilateral ceasefire, but Colombian government officials resisted the overture, saying the guerrillas had used previous ceasefires as an opportunity to take over large swaths of the countryside.

Santos said Monday that he expected the final peace deal to be reached by July 20.

A referendum then would be called for Colombians to vote on whether to accept or reject the agreement.