SELLS, Ariz., June 27, 2013— -- In Southwest Arizona, where the U.S. and Mexico borders meet, the U.S. Border Patrol has made huge strides in capturing border crossers and seizing drugs from Mexican cartels, but there is one stretch of land along the border that has made life a daily hell for a tribe of Native Americans.
The Tohono O'odham Nation, a Native American reservation about the size of Connecticut, is located in the Sonoran Desert, about 60 miles south of Tucson, Ariz., right on the U.S. border with Mexico.
Here, there is no barbed-wire high fence, but open desert, with only a vehicle barrier meant to stop cars but not people.
It is an area where the U.S. government has the fewest resources and the widest open space to patrol, making it a hot spot for Mexican drug cartels and human smuggling operations.
"Nightline" spent 48 hours with U.S. Border Patrol agents and the Tohono O'odham reservation police force to get a firsthand look at the battle on the border.
"The Tohono O'odham Nation is one of our most problematic areas," Arizona Commander Jeffrey Self of the U.S. Border Patrol told "Nightline". "The narcotics smugglers have moved up into the mountainous area. There is not a lot of access."
While border-crossing apprehensions in Arizona are down 43 percent from two years ago, it is a different, more complicated story on the Tohono O'odham Nation. Drug seizures on the reservation are steadily climbing -- nearly 500,000 pounds of marijuana was seized last year, a number that has nearly doubled since 2010. Recently, Tohono O'odham police seized $1 million worth of marijuana in just one week.
But the Tohono O'odham tribal members are caught in the middle of a war between the Mexican drug cartels coming through their community and the U.S. Border Patrol officers who tribal members say have become more aggressive to stop them.
In the Tohono O'odham Nation is "The San Miguel Gate," an area on the U.S.-Mexico border considered to be sacred by the Tohono O'odham. It is the only place where Native Americans can freely walk across the border, but there, the only thing separating Mexico and the U.S. is a low fence guarded by a lone border patrol agent and a light pole powered by a generator.
Verlon Jose, a Tohono O'odham tribal leader whose family has lived on the reservation for generations, and other members of his tribe talked to "Nightline" at "The San Miguel Gate." Jose acknowledged that the Gate carries a myriad of problems.
"Drugs come through here, migrants come through here," he said. "We see harassment from individuals who are moving contraband north, moving migrants north. Homes broken into, vehicles broken into. It's gotten more aggressive."
Jose's cousin Francine Jose lives in a remote part of the reservation and estimated that her house is broken into about once a month by people crossing the border illegally. There is no cell service inside her house so she can't easily call for help -- according to authorities, the police response time to her house can take up to 45 minutes -- and she said the border crossers who walk across her property know it.
"They are constantly breaking in all the time," Francine Jose said. "There was one just recently where they cooked stuff, about a month ago, slept."