PHOENIX - Reports of human smuggling aren't just limited to along the Arizona-Mexico border, according to authorities who say loads of illegal immigrants are routinely being transported on roads and highways through northern Arizona.
State police and other law-enforcement agencies say they regularly encounter the smuggling vehicles during traffic stops on rural highways and on Interstates 17 and 40.
Officials say tens of thousands of illegal immigrants could be traveling through northern Arizona every year.
But when police in that part of the state stop illegal immigrants, they are often forced to let them go because they don't have the authority to detain them.
Immigration enforcement is a federal responsibility, but there is no federal law-enforcement presence north of Phoenix.
If Immigration and Customs Enforcement is unable to respond, then the illegal immigrants are released, said Lt. Jim Gerard, commander of the Arizona Department of Public Safety's Flagstaff region.
In recent years, the Department of Homeland Security has added hundreds of Border Patrol agents to southern Arizona and deployed hundreds of National Guard soldiers along the Mexico border in an effort to stem the flow of illegal immigration.
The government also has added dozens of agents and beefed up resources in the Phoenix ICE office to help dismantle and combat organized smuggling rings and reduce smuggling-related violence.
The northern part of the state, however, remains open to smugglers, said Alonzo Pea, ICE's special agent in charge of investigations in Arizona.
"I know it's a vulnerability we have to address. The mere fact we have no presence there and the ability of smugglers to capitalize on that is great," Pea said.
Police in northern Arizona said they often don't call ICE because they know it can take hours for the agency to respond.
Many of the illegal immigrants are headed to Las Vegas and California, according to authorities.
ICE is considering opening an office in Flagstaff to combat smuggling in northern Arizona and to handle other immigration and customs violations.
In addition, ICE is training DPS officers to enforce federal immigration laws. Some of the DPS officers cross-trained by ICE will be assigned to northern Arizona.
The DPS officers will be authorized to question immigrant suspects about their legal status and detain them until they can be turned over to ICE, authorities said.