here's abc's marianna van zeller. >> reporter: high above the peruvian amazon, an elite police squadr battle. they're on a mission to stop the invasion of a ruthless enemy. drug cartels, hell bent on taking over this lawless jungle. all around us, vast fields of the raw ingredient for cocaine. a sign that the bad guys are close. on the ground, police fight the enemy with fire, destroying their hideouts and the labs where they manufacture drugs. it's just one bat until a raging war that could be spinning out of control. peru now produces more cocaine than any other country in the world. in part because cartels have found cover in this remote territory that boarders brazil and colombia. >> it's very far away, but it impacts us. >> reporter: this is the u.s. drug enforcement agency's regional director in south america. >> there is a possibility that cocaine from this border area is coming to the united states. it's not significant amounts just yet. but it is being diversified. >> reporter: and she believes the very same cartels that have been a menace to the u.s. for decades are now exp