QUITO (Reuters) - Ecuador’s President Lenin Moreno on Thursday gave a Colombian insurgent group 12 hours to prove that two journalists and their driver, kidnapped last month on their common border, are alive or their security forces would take joint action against them.

Moreno returned to his capital, Quito, from a regional summit in Lima, Peru, following unconfirmed reports that El Comercio reporter Javier Ortega, photographer Paul Rivas and driver Efrain Segarra were killed by a group of former fighters of the Revolutionary Armed Forces of Colombia (FARC).

Without specifying exactly what action would be launched once the deadline passed, Moreno said he had spoken to Colombia’s President Juan Manuel Santos and asked him to deal forcefully with the group, which funds itself via the illegal cocaine trade.

“I give these narcos 12 hours to give us proof of the existence of our compatriots otherwise we will go with all forcefulness,” Moreno told reporters.

“When I called President Santos this afternoon I told him we were asking for strong actions from them,” Moreno said.

Santos said on his Twitter account that Moreno could count on the support of Colombia’s armed forces.

On Wednesday, a statement apparently issued by the Oliver Sinisterra front - a faction of the former FARC guerrillas that refused to adhere to a 2016 peace agreement - reported that the Ecuadorians had died in a failed rescue operation.

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Colombia denied any rescue attempt and a day later a photograph appeared - which has not been released - that media has reported shows the bodies of three men.

The image is being analyzed by forensic analysts, but Ecuador’s interior minister, Cesar Navas, said he could not confirm if it was the three media workers.

The journalists and their driver were on assignment for the El Comercio newspaper when they were seized. A proof-of-life photograph released immediately after their kidnapping showed them chained and padlocked by the neck.

More than a thousand FARC fighters refused to demobilize under the accord with Santos and continue drug trafficking across the nation.

Those operating in Colombia’s southern jungles have attacked Ecuadorean security forces along the border.

The FARC, which battled for more than a half century, attacked military targets and civilian towns, but generally allowed journalists to work freely, unless they went against the rebels’ interests.