Colombia's second-largest rebel group, the ELN, released a civilian hostage Thursday, the Red Cross said, as the country seeks to salvage a peace process to end a half-century conflict.

"A civilian who was in the hands of the National Liberation Army (ELN) was handed over today to the International Committee of the Red Cross" in a remote area near the Venezuelan border, the humanitarian group said.

The news came as the government sought to save a peace deal with a larger rebel group, the Revolutionary Armed Forces of Colombia (FARC), that was rejected by voters in a referendum. The ELN has held preliminary talks with the government but has not yet joined the peace process.