The Colombian government and the country's second largest rebel group, the National Liberation Army (ELN), have announced the beginning of formal peace negotiations later this month, BBC News reports.
The talks will be launched in Ecuador's capital, Quito, on 27 October.
President Juan Manuel Santos urged both sides to be realistic in their demands, saying: "Time is the biggest enemy."
Santos is trying to salvage a peace accord with Farc rebels, which was rejected by voters earlier this month.
Informal talks with the ELN began three years ago, he said.
The announcement of an "open phase" in the negotiations was made in Venezuela, which will be one of the guarantors of the process.
The others will be Norway, Cuba, Chile, Brazil and Ecuador.
