Arizona driver arrested after 31 immigrants found in big rig

Agents assigned to the I-19 immigration checkpoint discovered 31 Mexican nationals inside the back of a tractor trailer. (U.S. Customs and Border Protection)

Authorities say an Arizona man has been arrested on suspicion of human smuggling after 31 Mexican immigrants were found in the tractor-trailer he was driving.

U.S. Border Patrol agents assigned to the Interstate 19 immigration checkpoint near Amado say the 40-year-old driver is a resident of Nogales, Arizona. His name wasn't immediately released Tuesday.

They say a Border Patrol dog alerted agents to the big rig for a secondary inspection and they discovered the immigrants between the ages of 15 and 40 all sitting in the cargo trailer.

A scan of a tractor trailer showed agents 31 Mexican nationals inside.

Authorities say they will be processed for immigration violations.

Border Patrol officials say the Department of Homeland Security launched "Operation Safeguard" to educate the trucking industry on the life-threatening dangers involved in using commercial vehicles to smuggle humans.