LAREDO: Mexico condemned the "recurring deaths" of nationals in US immigration custody after the death of the 18th Mexican in detention since president Donald Trump's return to the White House.
Hundreds of thousands of migrants have been arrested across the US as Trump looks to fulfill an election pledge to carry out the largest deportation operation ever.
Mexico's foreign ministry said the migrant died at a processing centre in Laredo, a city on the US-Mexico border.
It did not identify the person but said his family had been contacted.
The latest death was the first since Mexico filed criminal complaints in July over the deaths of 17 nationals who died while in US immigration custody, making it the 18th since Trump's inauguration in January 2025.
Immigration and Customs Enforcement (ICE) had not reported the death.
"Mexico expresses its deep concern over the recurring deaths of Mexican nationals while in custody or in the context of immigration operations in the US," the foreign ministry said in a statement.
It is a "situation that demands an effective response from the US authorities," it said.
The government also called for "a prompt, thorough, and transparent investigation" into the case.
It said it would also file a complaint over the most recent death.
At least 30 people died in US migrant detention centers last year - the largest number since 2004, the year after ICE was created.