The impoverished seaside strip has been controlled by the militant group for more than a decade.
Canada would be the second country in the world to make pot legal nationwide.
Lawyers and medical providers who have visited the South Texas shelters described playrooms of crying preschool-age children in crisis.
The accused were arrested in connection with a migrant-smuggling operation after a deadly chase, prosecutors said.
The announcement comes a day after the U.N.'s top human rights official criticized the Trump administration's "zero tolerance" immigration policy.