Colombia's last active rebel group yesterday declared a five-day ceasefire for the country's presidential election.

The announcement from the National Liberation Army came after peace talks resumed Thursday in Havana, Cuba.

"The ELN will stop military activities from zero hour, May 25, to 24:00 on the 29th to provide favorable conditions permitting Colombian society to express itself in the elections," the group said, using its Spanish acronym.

The rebels' magazine Insurreccion carried the announcement in its latest issue, as did the guerrillas' Twitter account.

Colombia's government had said it hoped for agreement on a ceasefire before the May 27 ballot.

President Juan Manuel Santos is trying to conclude a peace agreement with the ELN similar to one signed with the larger FARC guerrillas in November 2016.

The FARC has since become a political party.

Santos steps down in August and has admitted that any peace deal with the 1,500-strong ELN will likely come too late for him to sign.

The opinion polls' favorite to succeed him, right-wing senator Ivan Duque, is opposed to negotiations with the rebels.

Santos ordered his team to resume peace talks in March in response to a unilateral ceasefire by the ELN for that month's legislative elections.

Gustavo Bell, head of the government delegation, told reporters on Thursday that the talks would focus on building "a more robust ceasefire" than a 101-day truce that ended in January after Bogota accused the rebels of a spate of deadly attacks.