From this:

U.S. Border Patrol agents were backed down this week by armed men, dressed in what appeared to be Mexican military uniforms and carrying military weapons, who seized a captured dump truck filled with marijuana from the U.S. agents and dragged it across the border into Mexico with a bulldozer.

The border incident occurred Thursday evening when Border Patrol agents attempted to pull over a dump truck on Interstate 10 in Hudspeth County, Texas. The driver fled from the agents, exiting the freeway and driving toward the Rio Grande which runs within 2 miles of the interstate in this portion of West Texas.

The driver abandoned the truck after it became stuck in the river bed, escaping into Mexico...

The BP agents called for backup and began removing marijuana bales from the truck. Then, the uniformed Mexicans showed up. No shots were fired.