National Liberation Army (ELN) rebels on Thursday denied planning an attack on Colombia's capital Bogota, despite a warning from Cuba.

But the leftist guerrillas insisted they would not renounce "military action" against the state.

Colombia's Defense Minister Diego Molano reported on Monday that Cuba had tipped off the government about a plan by the ELN, Colombia's last remaining active armed rebels, to attack Bogota in the "next few days."

On Wednesday, Bogota Mayor Claudia Lopez said the capital was taking the threat "very seriously" and had stepped up security.

"After verifying with all guerrilla structures ... we clarify that the information received by the Cuban embassy in Bogota is not part of the ELN's military plans," the rebels' high command said in a statement.

It added, however, that it would be "naive" to expect the rebels to cease their armed operations.

The National Liberation Army (ELN) is the last active rebel group operating in Colombia
The National Liberation Army (ELN) is the last active rebel group operating in Colombia AFP / Luis ROBAYO

"This must be arranged around a negotiating table with an equivalent behavior on the part of the state," said the ELN statement.

The ELN speculated that the Colombian intelligence services were behind the warning released by the Cuban embassy with the objective of attributing attacks to the guerrillas to increase international pressure on their delegation based in Cuba.

Since 2018, Havana has hosted an ELN delegation that was negotiating a peace deal with former president Juan Manuel Santos (2010-2018).

But right-wing President Ivan Duque called off the talks following a car bomb attack on a police academy in January 2019 that killed 22.

Since then, Duque has demanded Cuba extradite the rebels on its territory to Colombia, but the island nation has refused.

The administration of former US president Donald Trump included that as a reason for putting Cuba back on a list of countries that sponsor terrorism.

The ELN has around 2,300 fighters and an extensive support network in urban centers.