At least 11,333 migrants were kidnapped in Mexico during a six-month span of 2010, the majority of them Central Americans, Mexico's National Human Rights Commission said Tuesday.
The governmental rights commission said Mexico's drug cartels snatched many of the migrants either to extort money from their relatives, or to recruit them to work for the gangs.
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 Mexican government has taken steps to try to guarantee better treatment for migrants, but a new immigration law being discussed in the Mexican senate could mark a step backward, some critics say.
The bill would guarantee rights like education, health care and equal treatment for migrants, but would also allow federal police to detain migrants without proper documents. Mexico's immigration officers are currently the only officials with such power, and the Mexican government has opposed the use of police to detain migrants in the United States.
The proposed legislation would also impose fines on those who hire undocumented migrants, a tactic also used in the United States.
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 Tomas Gonzalez Castillo reported that at least a dozen migrants had been kidnapped by an armed gang in the Gulf coast state of Tabasco late Saturday.
Gonzalez 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.