The National Institute of Migration said on Saturday that 129 migrants had been crammed into the back of a cargo truck by Mexican officials.
According to a statement, the “migrants from Guatemala, Honduras, El Salvador, and India” were found on Friday night in the eastern state of Veracruz.
At least eight individuals have died as a result of the heat wave now affecting Mexico.
The National Meteorological Service predicts that the village of Sayula de Aleman, where the vehicle with the migrants was discovered, would reach a temperature of 44 degrees Celsius (111 degrees Fahrenheit) on Sunday.
51 migrants from Guatemala, according to the migration institute, were sent back there.
The remainder were sent to a migration station, and 19 more unaccompanied youngsters from Guatemala and Honduras were moved to a special facility.
Thousands of migrants cross Mexico every day in an effort to reach the United States, many of them escaping poverty and violence in their home countries.
They frequently become victims of human traffickers or organized crime organizations along the journey.
According to the National Institute of Migration, more than 2,100 migrants were kidnapped in Mexico last year.