Mexican authorities detained more than 500 undocumented migrants over the weekend, mostly Central Americans trying to reach the United States, many of them risking their lives, officials said.
Many of the migrants, who were detained in six different operations, were being trafficked by smugglers in unventilated trucks with no food or water.
More than 200 others were found crammed into six “safe houses” used by criminal gangs in the state of Tamaulipas, which borders the United States.
They had paid their traffickers up to $4,000. More than 100 of the migrants in that group were minors.
The detentions come as immigration across the southern US border is at the center of a political firestorm in Washington.
The US Congress launched debate Monday on a proposal from President Donald Trump to grant citizenship to 1.8 million immigrants brought to the United States as children — a concession to opposition Democrats — in exchange for tough cutbacks on immigration and $25 billion for tighter border security, including his planned wall.