Updated

Mexican officials say a running series of gunbattles left at least 11 people dead in the northern border state of Tamauilpas.

The level of violence forced authorities to break up road blockades and use a helicopter to support ground patrols.

Officials discovered eight bodies Monday following shootouts in the border city of Reynosa and the nearby town of Rio Bravo, and police found improvised armored vehicles, grenades and about three dozen guns. The dead included a man apparently killed by assailants after he and a child sought shelter from gunfire on their way to school.

Three people were killed in the town of Padilla, farther south.

Reynosa is across the border from McAllen, Texas, and has been the scene of turf battles between factions of the Gulf cartel.