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, authorities said Wednesday. The government of the northern state of Tamaulipas said that the battles began with an ambush-style attack that killed two federal police officers on 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. According to the government, two passing motorists were also killed by stray bullets. Taamaulipas drug gangs often weld steel plates onto normal vehicles. The Tuesday confrontations continued at other points in the city, and gang members used passenger buses to block streets.