Mexican President Felipe Calderon said Monday that 61 men who had been kidnapped by a drug cartel before soldiers rescued them were migrants.
Calderon said Monday that kidnappers working for the Zetas cartel were holding the men captive in the northern border city of Piedras Negras until their families paid ransoms.
The three alleged kidnappers are now in custody of federal prosecutors.
A day before, Mexican army Gen. Luis Crescencio Sandoval Gonzalez said the migrants were held captive by the Zetas for use as forced labor. But the Mexican Attorney General's Office did not confirm that was the case in a Monday statement.
Soldiers found the men Saturday at a safe house guarded by three of the alleged kidnappers after a string of shootouts between soldiers and gunmen erupted in the city. Soldiers also found an abandoned truck filled with 6 tons of marijuana before the discovery of the migrants.
Federal prosecutors say cartel workers intercepted the migrants outside a bus station in Piedras Negras and lured them to go with them by falsely offering to bring them into the United States for charges ranging from $600 up to $3,000. One of the migrants rescued was from Honduras and the others were from various parts of Mexico.
Piedras Negras is across the border from Eagle Pass, Texas, in the Mexican state of Coahuila, which has been the scene of ongoing battles between drug gangs.