bogota bomb attack colombia leftist eln rebel group halt pump operations along country second-largest oil pipeline cano-limon covenas source military state oil company ecopetrol say monday attack take place rural el carmen municipality norte de santander province near border venezuela source say bomb cause crude spillage nearby river source speak condition anonymity official announcement yet make production cano limon oilfield operate u.s.-based occidental petroleum corp export affect source say ecopetrol officials say team company area carry clean-up operations repair expect take several days say attack pipeline leave 751 victims last 17 years include 167 deaths since 1986 pipeline service 3,800 days 10.4 years 30 percent life 66 million gallons crude spill since 2000 accord ecopetrol figure 485-mile 780-km pipeline carry 210,000 barrel per day national liberation army eln consider terrorist group unite state european union frequently attack colombia oil infrastructure group five-decade war government despite peace talk begin government february eln continue pipeline attack oppose presence multinational company mine oil sector claim seize natural resources without leave benefit country population economy colombia halt cano-limon pipeline rebel attack source