The talks were suspended in January after multiple guerrilla attacks on police and oil infrastructure, but were resumed a day after congressional elections.
“Thinking about life, saving lives, achieving a complete peace for Colombia, I have decided to resume peace talks with the ELN,” Santos said from the presidential palace.
Santos said he instructed lead negotiator Gustavo Bell and his team to return to Quito to resume peace talks.
ELN attacks have killed 19 members of the armed forces since the ceasefire ended. The Colombian armed forces said they have killed 34 rebels since then.
“We join President Santos’ call to restart talks, with the conviction that it is better to have dialogue in the midst of a bilateral ceasefire,” the guerrillas said in a statement.
Santos said that dialogue will resume with the purpose of agreeing to a new “comprehensive and verifiable” ceasefire agreement to avoid further casualties.
“Since the bilateral ceasefire ended, there have been too many deaths on both sides, too many wounded, too many victims. This is what we must stop,” Santos said.
The guerrillas blamed the “prolonged recess” of negotiations on government appeasement of the “far-right” in Colombia.
“The extreme right-wing violence is not for a political solution to the conflict, it is not ready to change, even a little, so that the Colombian majorities have more dignity, as individuals and as a nation,” the guerillas added.
Negotiations face the pressure of elections potentially changing government leadership towards right-wing parties who have stated their intention to relaunch an offensive against the radical armed group.