HAVANA (AP) — Colombia's government and its largest rebel group have signed a new, modified peace agreement following the surprise rejection of an earlier deal by voters in a referendum.

Chief government negotiator Humberto de la Calle says that he and rebel negotiator Luciano Marin, alias Ivan Marquez, signed the deal in Cuba, moving to put an end to a half-century-long conflict that has claimed more than 220,000 lives. It was unclear if or how the modified deal would be submitted to a referendum.

Santos and the Revolutionary Armed Forces of Colombia signed an initial peace deal on Sept. 26. But voters rejected it on Oct. 2 by just 55,000 votes, dealing Santos a stunning setback.

On Saturday, De la Calle said the negotiations had been intense. "We worked 15 days and nights to reach this new agreement."