Police in far northern Mexico have freed 52 people who were seeking to illegally cross into the United States but were were being held hostage by criminals.
The state of Tamaulipas said in a statement late Tuesday that police in the border city of Reynosa found the would-be migrants -- 48 Guatemalans, two Salvadorans and two Mexicans -- after two suspected criminals they picked up confessed to the kidnapping.
The immigrants told police they had been held for several days against their will, the statement said.
Mexico's National Human Rights Commission estimated in 2011 that, each year, some 20,000 people are kidnapped as they make the trek to the country's northern border with the United States.
The kidnappers usually ask relatives of the victims, who often live in the United States or Central American, to send ransom money.
On June 4, the Mexican army set free 165 immigrants in Tamaulipas state, 150 of whom were from Central America, who said they had been been kidnapped for weeks as they prepared to attempt to cross the US-Mexico border.
Tamaulipas is one of the most crime-ridden areas of Mexico. In August 2010, police found the bodies of 72 migrants from Central and South America at a remote ranch that were murdered by the Zetas drug cartel.