President Juan Manuel Santos will travel to Cuba today to unveil details of the deal with the Revolutionary Armed Forces of Colombia, or FARC.
UN secretary-general Ban Ki-moon announced he also would be present to witness the signing of the agreement.
The presidents of Cuba, Venezuela, and Chile — the three nations sponsoring the now almost four-year-old peace talks in Havana — were also expected, and the Obama administration was sending its special envoy to the talks, former diplomat Bernard Aronson.
Colombia’s conflict has killed more than 220,000 people and displaced millions since 1964. But a 15-year, US-backed military offencive thinned the rebels’ ranks and forced its ageing leaders to the negotiating table in 2012.
Momentum had been building toward a breakthrough after Santos said this week he hoped to end a half-century of bloodshed by July 20, marking Colombia’s declaration of independence from Spain.
But yesterday’s agreement went further than expected, removing all doubt a final deal is around the corner.
In addition to announcing a framework for the cease-fire, both sides said they agreed on how the FARC’s estimated 7,000 fighters will demobilise and hand over their weapons, as well as the security guarantees that will be provided to leftist activists after the conflict ends.
Negotiators in January tasked the UN with monitoring adherence to an eventual ceasefire and resolving disputes emerging from the demobilisation.
With the latest advances, only few minor pending items remain, the biggest being how the final deal will be ratified and given legal force so that it won’t unravel should a more conservative government succeed Santos, who leaves office in 2018.
Santos has vowed to put the deal to a referendum vote so Colombians can express their opinion.
Opinion polls show the FARC are widely despised among conservative Colombians and frustration with the rebels has grown as the talks have dragged on, making reconciliation seem more distant.
The peace talks have been bumpy and extended much longer than Santos or anyone else anticipated. But if a final deal is reached, it would end Latin America’s last major insurgency.
Still, the much-smaller and more recalcitrant National Liberation Army has a toehold in some areas and could fill the void left by the FARC. The FARC called a unilateral ceasefire nearly a year ago and the government responded by halting air strikes on rebel camps.
Negotiators missed a self-imposed deadline for signing a deal in March.