QUITO, Ecuador — President Juan Manuel Santos of Colombia and the leader of his country’s largest guerrilla group said Tuesday that the two sides would soon sit down to a new phase of peace talks with the goal of ending the long conflict.

Mr. Santos, speaking in Bogotá at the presidential palace, said the talks with the group, the Revolutionary Armed Forces of Colombia, or FARC, would begin in the first half of October in Oslo and would later move to Havana.

The leader of the FARC, Rodrigo Londoño, who uses the nom de guerre Timochenko, spoke about the talks in a videotaped message played at a media event held by guerrilla representatives in Havana. Both speeches were broadcast on national television in Colombia.

While both men spoke of their hopes for peace, the style of the two speeches was very different.

Mr. Santos, 61, dressed in a dark jacket with a light blue tie, spoke in a moderate tone as he gave a characteristically polished address that included new details about the talks, which he announced last week in brief remarks. Seated on either side of him were top military officers and his cabinet ministers.