The mass shooting in the US city of El Paso that claimed the lives of at least 20 people will be handled as a case of "domestic terrorism," US authorities said on Sunday.
The announcement was made after Mexico declared that it would take legal action to protect its citizens in the United States. Of the 20 people killed in the mass shooting, at least six were Mexicans, reported Al Jazeera.
"We're going to do what we do to terrorists in this country, which is to deliver swift and certain justice," US attorney for the western district of Texas, John Bash said in a press conference, adding that the attack appeared "to be designed to intimidate a civilian population, to say the least".
The El Paso incident occurred on Saturday when a 21-year-old suspect opened fire with a rifle on shoppers and then surrendered to officers who confronted him outside the store, police said.
The incident was followed just 13 hours later by another mass shooting in Dayton, Ohio, that claimed the lives of nine people and injured 27 others. Hours later, a third mass shooting incident took place in Chicago and killed at least seven others.
Earlier in the day, Mexican Foreign Minister Marcelo Ebrard had said that the country would take legal actions "in the frame of international laws."
"The president has instructed me to ensure that Mexico's indignation translates into ... efficient, prompt, expeditious and forceful legal actions for Mexico to take a role and demand that conditions are established that protect ... Mexicans in the United States," Ebrard said in a video posted on Twitter.