Mexican soldiers killed four presumed kidnappers during a gunfight at a ranch in northeast Mexico, the army said Monday.
The Defense Department said in a statement that gunmen opened fire on troops who were investigating a tip about suspicious activity Saturday night at the ranch in the town of China, near Texas.
It said two adults and two children who had apparently been kidnapped were freed, and two other suspects were detained.
And authorities reported Monday that nine people were shot dead Sunday in the resort city of Acapulco, located in Guerrero state.
Guerrero state police said in a statement that the victims include a woman and her two children. Six others, including a retired navy captain, died in four separate attacks.
Also Monday, an inmate stabbed to death the acting warden of a prison in the city of Nuevo Laredo, across the border from Laredo, Texas.
Warden Rebeca Nicasio Vazquez was on an inspection tour of the prison when the inmate approached her and stabbed her in the neck, according to a statement from the Attorney General's Office of Tamaulipas state.
The inmate was restrained by guards after the attack. The warden had been inspecting the cell blocks to ensure prisoners had no hidden weapons.
Nicasio Vazquez had been in the post for about two months. Tamaulipas has been the scene of bloody turf battles between drug cartels, and many of the inmates at the state's prisons face drug or weapons charges.