Between 1962 and 1971, American aircraft sprayed millions of gallons of Agent Orange over southern Vietnam, in an effort to clear thejungle foliage that helped to hide communist guerrillas.
The BBC's Dan Collyns in Lima says soldiers killed inthe attack were part of that operation, which is focused on isolated jungleinthe Ene-Apurimac valley - a hotbed for traffickers and guerrillas.