At least six police officers were killed during a shootout with armed individuals travelling in a convoy of about 10 armoured trucks in Nuevo Leon state, authorities said.
"Four more policemen were injured and are already receiving medical attention," Xinhua news agency quoted the state's security department as saying.
The attack occurred between the towns of Lampazos and Colombia in the north of the state, where police were outnumbered by the attackers, who carried large-caliber weapons, according to the authorities.
President Andres Manuel Lopez Obrador has said that violence is one of the main challenges of his administration, which began in December 2018.
