Mexico City, Mexico - President Claudia Sheinbaum vowed to respond to the killing of a Mexican citizen by US Immigration and Customs Enforcement earlier this week by enacting "legal measures."

"We cannot permit the mistreatment of our brothers in the United States," Sheinbaum said during a press conference on Wednesday. "So we are preparing measures."

While her spokesperson declined to comment on the specific legal response the Mexican government will take, Sheinbaum did clarify it will "go beyond" a simple complaint to international bodies or a diplomatic statement.

"There's another regrettable death of a fellow national in the United States for detention matters, when their only offense is not having papers – despite being hired by a US company," she said in comments translated from Spanish.

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"So there's no reason for them to be in detention centers or use violence. So yes, we are preparing legal measures."

Sheinbaum's comments come after ICE agents gunned down Lorenzo Salgado during a vehicle stop in Texas on Tuesday morning. Salgado had lived in the US for 35 years, working in construction.

He is but the latest in a series of Mexican citizens who have died either during interactions with ICE agents, or while imprisoned in one of the US' notoriously inhumane detention camps.

Mexico has repeatedly condemned these deaths as "unacceptable" and pointed out that conditions within the camps are "incompatible with human rights standards and the protection of life." These claims have been supported by numerous reports.

Salgado's son spoke out about his father's death on Wednesday, demanding a full investigation. He was backed by the League of United Latin American Citizens, who said "the agency whose officers fired the weapon cannot be the agency that controls the narrative and the evidence."

"He did not deserve to die," said Ronaldo Salgado. "He deserved to live a quiet life."