The Mexican military has escorted drug smugglers into United States territory for years. On occasion, our Border Patrol agents are confronted, on US soil, by the Mexican army. In fact, there have been more than 200 confirmed incursions by the Mexican military into the United States since 1996. The latest case was on Sunday, August 3, 2008.
A Border Patrol agent, working south of Ajo, Arizona, encountered Mexican military personnel who had crossed over into the United States. The agent was held at gunpoint for a period of time, presumably while the smugglers they were protecting moved through the area. Thankfully, back-up officers arrived and the troops withdrew without a gun battle.
Unfortunately, not all US law enforcement encounters with the Mexican army have been as “peaceful.” For example, in January 2007, the Mexican army, in the United States, fired on Texas deputies with a .50 caliber machine gun.