Authorities say gunmen in homemade armored vehicles engaged in a day of running gunbattles that left 14 people dead in the Mexican border city of Reynosa, across the border from McAllen, Texas.

The government of the northern state of Tamaulipas says the battles began with an ambush-style attack that killed two federal police officers on a patrol.

The army was called in and came under fire from four gunmen in a pickup truck with improvised armoring. They were killed, as were six other gunmen in ensuing gunbattles.

The government says two passing motorists were also killed by stray bullets.

Tamaulipas drug gangs often weld steel plates onto normal vehicles.

The confrontations Tuesday continued at other points in the city, and gang members used passenger buses to block streets.