A Laredo Sector Border Patrol K-9 alerted to a tractor-trailer at an immigration checkpoint in South Texas. The trailer contained 66 migrants who were locked inside with no means of escape.

Agents assigned to the Interstate 35 immigration checkpoint observed a tractor-trailer rig approach for inspection. During the initial inspection, Laredo Sector Border Patrol officials reported that a K-9 agent alerted to the possible presence of drugs or human cargo in the trailer. The agents directed the driver to move the rig to a secondary inspection station.

The agents opened the trailer and discovered 66 migrants who had been locked inside the trailer with limited ventilation and no means of escaping in the event of a crash or abandonment by the human smugglers. Agents said the 66 migrants included two juveniles.

The Interstate 35 checkpoint agents conducted initial medical screening and immigration interviews. The agents determined that all of the migrants were in good health. They identified the migrants as having come to the U.S. from Ecuador, Guatemala, and Mexico. None had any legal authorization to be in the United States, officials said.

“The Laredo Sector Border Patrol will continue to warn against the dangers of people crossing illegally into the United States through dangerous environmental conditions,” Laredo Sector officials said in a written statement. “Our Border Safety Initiative (BSI) is a humanitarian, bi-national strategy designed to reduce illegal alien deaths, educate and inform potential illegal aliens of the dangers and hazards of crossing the border illegally, and to respond to those who are in life-threatening situations.”

Border Patrol officials seized the tractor-trailer and placed the driver, a U.S. citizen, under arrest for possible charges of human smuggling. The 66 illegal aliens will be processed according to Laredo Sector guidelines.

Bob Price serves as associate editor and senior political news contributor for the Breitbart Border team. He is an original member of the Breitbart Texas team. Follow him on Twitter @BobPriceBBTX and Face book.