northwestern jungles colombia colombia eln guerrilla group say russian-armenian citizen hold hostage six months kill april try escape startle admission risk throw current peace talk government jeopardy rare interview commander national liberation army colombia last active guerrilla group say ransom kidnappings necessary keep fighters field peace would impossible without state fund fee clothe rebel eln seize arsen voskanyan november group claim collect endanger poisonous frog jungles northwestern department choco accuse want smuggle wildlife overseas lengthy captivity voskanyan shoot grab hand grenade bid escape accord eln commander would give nom-de-guerre yerson dead yerson tell reuters remote area along bank river see frequent combat leftist rebel government troop right-wing paramilitaries grenade explode ... several boys wound entire unit five boys flee shoot kill ... issue body negotiate say add death take place within unit yerson supply evidence back assertions another person knowledge matter also subsequently confirm voskanyan kill reuters could independently confirm circumstances surround voskanyan death colombia government say know nothing eln claim last know statement eln say escape responsibility eln senior official say ask name russian embassy colombia colombia high peace commissioner foreign ministry moscow immediately respond request comment eln practice kidnap civilians key issue peace talk take place ecuadorean capital quito fact voskanyan kill talk progress eln fail inform government may complicate already tricky negotiations end 53 years war make need agree ceasefire press make urgent get bilateral verifiable ceasefire soon possible keep happen leftist senator antonio navarro wolff belong now-demobilized urban guerrilla group m-19 tell reuters yerson troop say optimistic peace agreement reach neither side give grind kidnap eln refuse stop take hostages ransom launch bomb attack extort foreign oil mine company talk ongoing government say move forward issue like bilateral ceasefire talk eln hold revolutionary arm force colombia farc year big rebel group demobilize form new political party end part civil war kill 220,000 people displace millions five decades face cover thin black balaclava wear beret camouflage fatigue yerson 35 say fight colombia jungles mountains many many years flank two fighters carry semi-automatic rifle rebel watch question government willingness make sufficient concessions say would adhere wish leadership peace deal reach eln seek peace hold talk cuba venezuela 2002 2007 experts say discussions dog lack side yerson commander ernesto che guevara front fight command eln leader know uriel command western war block omar gomez decline say many rebel fight unit eln kidnap hundreds colombians foreigners economic political gain previously say statement voskanyan escape injure struggle leave several fighters wound try release international committee red cross kill voskanyan may turn already dire public perception eln analyst ariel avila tell reuters impact public opinion question talk say inspire cuban revolution establish radical catholic priests 1964 eln close disappear 1970s steadily gain power 2002 many 5,000 fighters finance war tax levy landowners oil company believe 2,000 fighters yerson would confirm number say group heavily recruit consider terrorist group unite state european union eln step attack economic infrastructure year hit oil pipelines power line repeatedly president juan manuel santos meted crush military blow farc earn nobel peace prize last year efforts peace less success eln move mobile units four fighters eln say may declare temporary ceasefire honor pope francis visit next week colombia exclusive colombia 's eln say kill russian hostage risk peace talk government