Such migrants are often preyed on by organized crime gangs and drug traffickers as they try to make their way north to the United States in search of work and a better life.

Troops acted Saturday night in the northeastern state of Tamaulipas after receiving a tip-off that people were being held against their will in a building, a source in the office of the state attorney general said.

Six people were arrested. Five of the victims were Mexicans and the rest from Central and South America, including six women and children.