"It's going to get more complicated the way we see it, especially human rights for those who are simply looking for an opportunity to benefit their lives," said García Lara. "There have been many instances where soldiers are simply looking for migrants to prey on.

The Mexican troops will be posted to hot spots along the border with high rates of illegal migration and drug and weapons trafficking.

A line of Mexican National Guard and Army trucks are rumbling along the border separating Ciudad Juárez and El Paso, Texas, among the first of 10,000 troops Mexico has sent to its northern frontier fo