Mexican authorities are sending 100 soldiers and helicopters crews to patrol one of the busiest highway corridors in the border state of Tamaulipas. The region is a haven for cartel gunmen.

Officials in Tamaulipas report a recent uptick in highway robberies and other crimes that reached a climax this week during a fierce shootout where two passenger buses became caught in the crossfire.

The municipality of San Fernando is one of the busiest farming areas in Tamaulipas. Highways in the area provide a steady flow of commercial and tourist traffic as it connects the central part of the state with the Texas border. The city is roughly 70 miles south of the Mexican border cities of Matamoros and Reynosa. Law enforcement sources revealed to Breitbart Texas that the region is currently controlled by a faction of Los Zetas called Vieja Escuela Z. The group is reported to be an ally of the Gulf Cartel.

This week, groups of rival cartel gunmen clashed around San Fernando leading to the deployment of Tamaulipas State Police officers and Mexican Army soldiers to stop the shootout. During the gun battles, two passenger buses from the Transpais bus line sustained multiple hits from stray gunfire after being caught in the middle of the shootout. Officials report no injuries to passengers of the two busses.

According to information released by the Tamaulipas government, a group of gunmen also parked a tractor-trailer across the highway and torched it in an attempt to keep authorities from the chasing cartel gunmen. The gunmen also placed a second blockade with various trucks along the highway that connects San Fernando with the border city of Reynosa.

As Breitbart Texas reported, Tamaulipas state authorities began carrying out a series of operations in recent days targeting a leading Gulf Cartel member who is reportedly linked to numerous highway robberies and rapes of motorists in the San Fernando area. As a result of those operations, authorities killed Esteban “La Princesa” Gonzalez and four of his gunmen last week. Despite the death of La Princesa, San Fernando continues to be a hotspot for cartel activity.

Ildefonso Ortiz is an award-winning journalist with Breitbart Texas. He co-founded Breitbart Texas’ Cartel Chronicles project with Brandon Darby and senior Breitbart management. You can follow him on Twitter and on Facebook. He can be contacted at Iortiz@breitbart.com.

Brandon Darby is the managing director and editor-in-chief of Breitbart Texas. He co-founded Breitbart Texas’ Cartel Chronicles project with Ildefonso Ortiz and senior Breitbart management. Follow him on Twitter and Facebook. He can be contacted at bdarby@breitbart.com.

“A.C. Del Angel”, “J.A. Espinoza” and Tony Aranda from Breitbart Texas’ Cartel Chronicles project contributed to this report.