He said elite troops would soon be deployed to the northern border area where the employees of El Comercio newspaper were last seen nearly three weeks ago while investigating a rise in drug-fueled violence. Colombian President Juan Manuel Santos dispatched his top military advisers to Quito to assist in the military planning.
Moreno also offered a $100,000 reward for information leading to the capture of Walter Arizala, better known by his alias Guacho, the leader of a holdout group of guerrillas from the demobilized Revolutionary Armed Forces of Colombia that claimed responsibility for the kidnapping.
Fears that the kidnapping had ended in tragedy emerged Thursday when a Colombian TV network said it had received gruesome photos purporting to show the bodies of the three men.
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However forensic experts in both countries were unable to confirm the authenticity of the images, exasperating press groups and family members who say the government had been taking the incident too lightly.
Moreno on Thursday night rushed back from a regional summit in Peru to deal with a crisis that has shaken Ecuadoreans' long held self-identity as a tiny, peaceful nation insulated from the drug-fueled violence raging across its border. In a late-night press conference, he said there was an "enormous possibility" the deaths were real and on Friday said authorities had obtained new, unspecified information that confirmed the three men had been killed.
As Moreno spoke, dozens of colleagues and friends of reporter Javier Ortega, photographer Paul Rivas and their driver Efrain Segarra gathered in mourning in a plaza outside the presidential palace under the slogan "Three Are Missing," the same one that has featured in candlelight vigils held almost every night since their disappearance.
Both the Ecuadorean and Colombian governments have tried to limit the fallout from the kidnapping, with officials in both countries denying the men were being held inside their territory and even squabbling over Guacho's supposed nationality.
Earlier this week, authorities dismissed as fake a statement signed by the captors claiming the journalists were killed during a military raid coordinated by the two governments.
"We condemn the actions of the Colombian and Ecuadorean governments and their lack of seriousness in protecting the reporters' lives," Colombia's Foundation for Press Freedom said in a statement Thursday.
Moreno's promise of a "devastating" military response was seen by many as a tacit acknowledgement that both governments had been too restrained.
"When there is cooperation between the two countries the criminal will always fall," Santos said from the Summit of the Americas in Peru, promising to work closely with Moreno on a military campaign.
In a proof-of-life video released earlier this month, the three men identified their captors as members of the Oliver Sinisterra Front, a group of a few dozen combatants that authorities say is led by Guacho, a former FARC rebel. The group is believed responsible for recent deadly attacks in northern Ecuador against military targets.
Moreno announced last month that he was sending 12,000 soldiers and police to combat drug gangs and boost security along the border. That represents about 10 percent of the small nation's police officers and troops.
Ecuador is a major transit zone for Colombian-produced cocaine, with small boats carrying the drugs from the South American nation's Pacific shore to Central America and on to the United States.
Goodman reported from Bogota, Colombia.