Mexican marines killed six suspected criminals after gunmen opened fire on a Black Hawk helicopter in the violence-hit northern state of Tamaulipas on Sunday.
None of the marines aboard the helicopter were hurt when it was hit by seven bullets, a navy statement said.
"The attack was repelled, resulting in the deaths of six people among the group of assailants," the navy said.
The authorities seized four vehicles and six weapons after the attack
The helicopter was on mission searching for members of drug cartel when it found a group of gunmen in a rural area about 70 kilometres south of Nuevo Laredo, a city at the US border.
The incident comes two months after suspected members of the Jalisco New Generation drug cartel downed a Cougar helicopter with a rocket-propelled grenade, in which six soldiers and a policewoman were killed.
Attacks on the security forces are frequent in Tamaulipas, where drug cartels have fought each other and the Mexican authorities for years as part of a turf war between rival drugs cartels.