Story highlights Colombian rebels have been fighting the government for more than 50 years

Landmark deal still faces approval in a referendum set for October 2

Havana, Cuba (CNN) Negotiators seeking to end the five-decades-old bloody insurgency in Colombia said Wednesday they had reached a final peace deal in one of the world's longest-running conflicts.

For nearly four years, representatives from the Colombian government and the FARC rebel group have struggled to reach a deal that would not only end the fighting but also address issues of land reform, curtailment of the drug trade, repatriation of victims' families and trials for those suspected of human rights abuses.

A majority of Colombians must still approve the landmark deal in a referendum set for October 2.

Provisions that allow FARC leaders who confess their crimes to avoid prison may make the deal a bitter pill to swallow for many Colombians who think the rebels are escaping justice for decades of murder, kidnapping and drug trafficking.

On Wednesday, President Barack Obama called Colombian President Juan Manuel Santos to congratulate him on the deal and pledge continued support to his government. The United States has given Colombia billions of dollars in aid to combat drug trafficking and terrorism, which helped kill top FARC commanders and led to scores of foot soldiers abandoning the group.

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