Mexican police stopped more than 500 illegal migrants from Asia and Central America in Chiapas, southern Mexico.

The 513 individuals were being transported in inhumane conditions in the trailers of two trucks, according to the authorities. The police spotted the migrants using X-ray machines at a checkpoint in Tuxta Gutierrez, and then pursued the trucks until they stopped, reports EFE.

Investigations suggest that the passengers each paid $7,000 to be transported to the U.S. There were migrants from Guatemala, Honduras, El Salvador, Ecuador, and the Dominican Republic, as well as China, India and Nepal.

Migrants trying to make their way to the U.S. often face kidnapping and abuse from drug gangs on their way through Mexico — see InSight’s map of the most dangerous routes.