A technical committee set up to thrash out the details of a new ceasefire formally began work in Havana on Friday, a brief joint statement said.

The committee is composed of members of the negotiating team as well as military officers, government representatives and ELN delegates, it said.

Colombia's last active rebel force, the National Liberation Army (ELN), resumed preliminary peace talks with the government last week in Havana.

The rebels said Monday they would observe a five-day ceasefire for the presidential election.

Both sides have expressed a willingness to reach a deal for a longer ceasefire than the one which ended in January after 101 days. That fell through amid mutual accusations of breaches, and a spate of rebel attacks on the military.

Cuba stepped in to host the talks after Ecuador -- which hosted several rounds of talks over a 15-month period since February 2017 -- pulled out last month in protest over an upsurge of violence on its border with Colombia.