Government negotiator Juan Camilo Restrepo said on Friday an operation was under way for the leftists to hand former Colombian congressman Odin Sanchez over to the Red Cross.

"We have been informed by the Red Cross that it has begun the operation to free ...Sanchez, held hostage for six months by the ELN, with help from the Catholic church," said Restrepo.

Santos postponed peace talks with the left-wing National Liberation Army (ELN) on Thursday - hours before they were due to begin - insisting that the group first release a former lawmaker being held hostage.

The president said he was committed to making peace but would not be swayed from his demand that the ELN free Sanchez "safe and sound."

Interior Minister Juan Fernando Cristo said the government could reschedule the talks to Friday, Saturday "or whenever we are certain that Odin Sanchez has been freed."

Sanchez went into the custody of the ELN voluntarily in April in place of his brother, a former governor who had become ill after three years in captivity.

'Terrorist act'

Hours after the government suspended the talks, ELN rebels killed two truck drivers in the country's northeast. The country's military described it as a "terrorist act" against two civilian vehicles.

The talks with the ELN were supposed to mark a new phase in Santos' efforts to bring peace to the country.

The ELN is Colombia's second-largest rebel group behind the Revolutionary Armed Forces of Colombia (FARC), with whom Santos has already signed a peace deal this year, winning a Nobel Peace Prize.Voters rejected the terms of that accord earlier this month, meaning that negotiations are back to the drawing board.

rc/mm (EFE, AFP)