Colombian President Ivan Duque has announced a crackdown on the guerrilla group National Liberation Army (ELN) following a deadly car bombing, and asked Cuba to arrest 10 of its peace negotiators who are on the Caribbean island.
The ELN staged Thursday's "contemptible attack" against a Bogota police academy that left 21 people dead and dozens injured, Duque said in a televised address.
"The ELN has no will to peace," the president said, calling on it to hand over the 16 kidnapped people it is holding and to "stop all criminal activity".
Duque's predecessor Juan Manuel Santos was holding peace talks with the group in Havana, but Duque suspended the negotiations after taking office in August.
He has insisted that negotiations cannot be resumed unless the ELN unilaterally releases all of its abductees and stops all attacks.
The president now said Colombia was reactivating arrest warrants against 10 ELN negotiators who are in Cuba and asked Havana to hand them over.
Colombia will "denounce any state" hosting ELN members in its territory, Duque said in an apparent reference to Venezuela.
"You can be certain that we are prepared to continue confronting all criminal organisations," the president said, vowing the dismantle the ELN's "structures" of drug trafficking, illegal mining and smuggling.
Jose Aldemar Rojas Rodriguez, who drove a van loaded with explosives to the premises of the police academy and who died in the explosion, was a long-time member of the ELN, Attorney General Nestor Humberto Martinez and Defence Minister Guillermo Botero said at an earlier press conference.
Rojas had worked as an explosives expert for the group and trained its members in the use of explosives in Venezuela, Botero said.
Diosdado Cabello, president of Venezuela's pro-government Constituent Assembly, denied that his country had anything to do with the attack.
"Today the Colombian bourgeoisie and oligarchy, together with its Venezuelan lackeys, are trying to link Venezuela with terrorist acts in Colombia," the daily El Universal quoted Cabello as saying.
"We have nothing to do with that war, we condemn any terrorist act and hoist the flags of peace," he added.
Colombian police meanwhile arrested another man, Ricardo Andres Carvajal, who confessed to helping Rojas organise the attack, Martinez said.
Dozens of people on Friday gathered in front of the police academy to leave flowers and express their solidarity. Duque had decreed three days of mourning.
United Nations Secretary General Antonio Guterres said he "strongly condemns" the attack in a statement released by his spokesman.
"The Colombian authorities have indicated that they have proof that this terrorist act was conducted by the ELN. The perpetrators must be brought to justice," Guterres said.
The ELN, which has an estimated 1500 fighters, is Colombia's last officially existing guerrilla group after Santos signed a peace deal with the much bigger FARC in 2016.
The ELN has kidnapped dozens of people, for ransom and political leverage, in the past few years. On January 11, the group shot down a helicopter belonging to a private company and abducted its three crew.
Peace commissioner Miguel Ceballos said there was "no room for a dialogue with the ELN" until it met the conditions set by the government.
