Mexican President Claudia Sheinbaum has vowed to take action after the death of another Mexican national in US immigration custody.
Jose Guadalupe Ramos-Solano died last week at a detention centre in Adelanto, southern California - the fourth fatality at the facility this year.
He is the 14th migrant to have died in Immigration and Customs Enforcement (ICE) custody this year. His cause of death has not yet been determined.
Mexico's government is filing a legal brief as part of a class-action lawsuit alleging unconstitutional conditions at the centre. The number of immigrants in ICE custody is among the highest ever, with 68,000 held as of last month.
Ramos-Solano, 52, died on 25 March while being held at the Adelanto ICE Processing Center, the agency said.
