More than 11,000 migrants crossing Mexico were kidnapped and either held for ransom or conscripted into criminal gangs during a six-month span of last year, said Mexico's National Human Rights Commission on Tuesday.
Forty-four percent of the migrants kidnapped during the period studied — April through September — were from Honduras, 16.2 percent from El Salvador, 11.2 percent from Guatemala, and 5 percent from Cuba.
A previous study by the commission had found 9,758 migrants were kidnapped from September 2008 to February 2009, but it was not clear if seasonal variations caused the increase seen in the latest study.
The commission said the cartels usually demand families pay from $1,000 to $5,000 to win the release of a migrant.
It also said fellow migrants are sometimes used as informants by the gangs to help in kidnappings.
"There are Central American migrants in the organized crime groups that kidnap migrants," said commission president Raul Plascencia.
The infiltrators mingle with other migrants to find out who has relatives in the United States able to pay ransom, and sometimes even lead groups of fellow migrants to points where they can be kidnapped.
Migrants are often subjected to extortion, robbery and other abuses as they cross Mexico trying to reach the United States.
Plascencia said Mexican authorities had taken some "isolated" actions to combat the kidnappings, but called for stronger efforts.
The kidnapping issue came to a head after 72 migrants from Central and South America were slain last August in a massacre in the northern Mexico state of Tamaulipas that authorities blamed on the Zetas drug cartel.
On Tuesday, Roman Catholic priest Tomás González Castillo reported that at least a dozen migrants had been kidnapped by an armed gang in the Gulf coast state of Tabasco late Saturday.
González Castillo heads a human rights group that defends migrants. He said he was told about the abduction by three migrants who escaped captivity and sought shelter in his parish.
The Associated Press contributed to this report.