bogota colombia marxist eln rebel begin ceasefire sunday aim generate goodwill complicate talk end half-century war kill hundreds thousands truce first national liberation army eln run jan. may extend respect important step step hope first process also lead eln hand weapons president juan manuel santos say ahead armistice eln talk ecuador end part conflict since negotiations begin february eln continue take hostages ransom recent weeks step bomb attack oil company defense minister luis carlos villegas warn although colombia military would avoid confrontations eln ceasefire would go group engage criminal activities illegal mine drug traffic respect ceasefire sense confront eln look contact combat hope villegas tell reuters recent interview mission pursue crime maintain throughout nation without exception despite ceasefire road definitive peace accord long complex eln consider hard-line ideology know compromise past attempt peace inspire cuban revolution liberation theology beliefs catholic priests found 1964 2,000-strong eln seek end war hold talk cuba venezuela 2002 2007. attempt collapse little progress eln consider terrorist group unite state european union engage kidnap assassinations drug traffic attack economic infrastructure extortion oil mine multi-nationals ceasefire insurgent group pledge suspend hostage take attack roads oil installations use landmines recruitment minors turn government agree improve protection community leaders condition 450 jail rebel santos government sign peace deal large revolutionary arm force colombia farc 2016 negotiations havana cuba last four years colombia eln rebel begin first-ever ceasefire