Peace talks had been scheduled to restart this week after a recess between the ELN and the government of centre-right President Juan Manuel Santos.
Helen Murphy and Luis Jaime Acosta
The National Liberation Army (ELN) rebel group, which has bombed oil installations and kidnapped for ransom, was founded by radical Catholic priests in 1964.
Colombia’s government and the FARC signed a peace accord in September that was rejected in a plebiscite last month.
President Juan Manuel Santos and rebel leader Timochenko warmly shook hands on Colombian soil for the first time and signed the accord with a pen made from a bullet casing.