Mexican Foreign Minister Marcelo Ebrard says Mexico will take legal action to protect Mexicans and Americans of Mexican descent after the shooting in El Paso, Texas.
In a video statement, Ebrard called the shooting an "act of barbarism" and said the country's first priority is attending to the impacted families.
Next, he said, Mexico plans to seek legal measures to protect Mexican nationals and Mexican-Americans in the U.S.
Mexican officials say three Mexican nationals were killed and another six were wounded in the Saturday shooting at a Texas Wal-Mart.
El Paso is a popular weekend shopping destination for Mexicans who live across the border, in Ciudad Juarez.
The shooter appears to have been targeting Hispanics and authorities are investigating it as a hate crome.