Colombia's ELN rebel group provided proof of life for the two soldiers captured last month after guerrillas killed 12 members of the security forces in an ambush in the central province of Boyaca.

In a message broadcast on the ELN's clandestine radio station, the soldiers Andres Felipe Perez and Kleider Antonio Rodriguez said they were well and had not suffered any abuse at the hands of the insurgents.

"Up to now they have respected my human rights without any mistreatment," Perez said, after sending greetings to his family.

For his part, Rodriguez seemed confident that he will soon be "reunited" with his dear ones and asked the government "to use the instruments at its disposal" to make their release "quick and without risk."

Both soldiers have been prisoners since Oct. 26 when the ELN ambushed a patrol in Guican, Boyaca, that was returning from an Indian reserve with the ballots cast in local and regional elections the day before.

The ELN, the smaller of Colombia's two main insurgencies, said on Nov. 2 that in the coming days it would free the soldiers, an intention it repeated Monday after the prisoners spoke on the radio.

The rebels also insisted that the prisoners "are safe and sound" in their custody, and that they are doing everything to protect them "despite the threats and the hefty military operations ordered to rescue them with guns and bloodshed."

At the same time, they said that the number of soldiers and police killed in the ambush did not make them "happy" because "they all had families."

The ELN concluded its message with a denial of claims that the insurgents gave coups de grace to the dead or that they hid explosives on their bodies to blow up whoever came to recover them.

The government and the ELN have had "exploratory" contacts since 2014 to launch a peace process similar to the one underway with the larger FARC guerrilla army, but have not been able to establish a negotiating agenda that would permit the formal opening of talks.