U.S. border police said Thursday they had found 51 illegal Mexican immigrants, among them a 5-year-old boy, hidden inside a refrigerated trailer carrying avocados into the United States.
Border agents said they found the Mexicans crammed into the back of the truck on Wednesday when police dogs sniffed humans among the avocados at a checkpoint just north of the U.S.-Mexico border near Laredo, Texas.
The truck was a chilly 57 degrees, U.S. border patrol spokesman Eugenio Rodriguez said.
"The illegals were thinly clothed. They could have begun to suffer hypothermia if they had been in there any longer," Rodriguez told Reuters by telephone.
The Mexicans were being detained at a border patrol detention center while a U.S. judge decided whether to deport them or send them to jail, he said.
Tougher border security has forced migrants to take more dangerous routes to cross into the United States, often finding elaborate hiding places to avoid detection and frequently paying to be taken over the border.
Migrant rights groups say at least 4,500 Mexicans have died trying to cross since the United States sharply stepped up controls in late 1994 to stem illegal immigration.
Last year in Texas, a truck driver was sentenced to life imprisonment for his role in the deaths of 19 of 70 illegal immigrants locked in a sweltering tractor-trailer in 2003, in the deadliest human smuggling attempt in U.S. history.