The United States has confirmed that an anti-drug plane that crashed in Colombia last month was shot down by hostile fire.
The Colombian Government is trying to eradicate drug crops
Rebels of the left-wing ELN said on Thursday that they had downed the US-owned aircraft, which crashed on 21 September.
A State Department spokeswoman in Washington told BBC News Online that the plane crashed in the Norte de Santandar region, killing its Costa Rican pilot.
"Preliminary information indicates it was struck by hostile ground fire," she said.
US-owned planes regularly spray suspected coca plantations in Colombia in an effort to stamp out the supply of cocaine.
The previous plane to be shot down crashed on 25 August, the spokeswoman said.
She said 320 rounds of hostile fire had hit spray aircraft this year.
The State Department says the increase in hostile fire indicates that the spray missions have been achieving their objective.
Search-and-rescue craft accompany the spray missions, the spokeswoman said.