The Mexican government says a man fatally shot by a U.S. Border Patrol agent was a Mexican citizen and it "deeply regrets" the incident.
The Foreign Relations Department said in a statement late Friday that "Mexico has repeatedly said the use of lethal force in immigration control and border security should be used as a last resort."
Border Patrol officials say the man assaulted the agent after illegally crossing the frontier near Yuma, Arizona, late Thursday.
The agent says he feared for his life and fired after the man hit him in the head and tried to take his gun.
The agent suffered cuts and bruises to his head, face and torso, as well as a concussion. He is on administrative leave.