Mexican officials say soldiers searching vehicles for hidden drugs found 140 Central Americans crammed into a tractor-trailer rig.
The Defense Department says troops trying to fight narcotics traffic and organized crime in the southern state of Chiapas found the migrants on Sunday. It did not say what country they were from.
Chiapas borders Guatemala and thousands of migrants traverse the state each year as they attempt to reach the United States.
Two men were detained in connection with the discovery. The migrants were hidden behind a false wall in the trailer.
In June, authorities found 210 dehydrated Central and South American migrants packed into a tractor-trailer in Chiapas.