Members of Colombia's ELN left-wing rebel group and government negotiators have begun talks seeking to end more than five decades of conflict, BBC News reports.
The negotiations were launched at a ceremony in the capital of Ecuador, Quito, where the talks will be held.
Delegates stood side by side as the Colombian national anthem was played.
The talks come just months after the government signed a peace agreement with Colombia's largest rebel group, the Farc.
The chief ELN negotiator, Pablo Beltran, urged both sides to rally around the points that united them and leave aside their differences.
The top government representative, Juan Camilo Restrepo, said he expected to draw from the lessons of the negotiations with the Farc to reach a peace accord with the ELN.
They both agreed that this was a once-in-a-generation opportunity for Colombia to achieve peace.
"Colombia and the world realise that it's very unlikely that this opportunity for peace will come before us again," said Mr Restrepo.
He called on the rebels to officially suspend its kidnapping policy during the negotiations.
The ELN relies on the ransom obtained from kidnappings or "retentions" to finance their activities.