The soldiers were in Roma, Texas when two shots were fired from across the border, according to the Texas Department of Public Safety. No injuries were reported, and the Texas Rangers are investigating the incident.
The suspected shooters are believed to be gunmen from a drug cartel, but it was not clear which one. The incident occurred in the same area where Fox News recently witnessed tracers from a suspected cartel machine gun while embedded with Texas Rangers.
The area in question is part of a bloody turf war between the Gulf Cartel and the Northeast Cartel, an offshoot of Los Zetas, one of Mexico's most violent organized groups known for committing beheadings and indiscriminate killings.
Heavily armed groups are becoming a more common sight along the Texas-Mexico border, authorities said. Last week, DPS officials told Fox News that suspected cartel members involved in human smuggling were wearing tactical gear and armed with AK-47s while taunting National Guard soldiers across the Rio Grande.
Mexican cartels have been known to commit acts of violence on migrants traveling to the U.S.-Mexico border, but it is rare for them to confront American law enforcement or military troops.
The reports come as migrants continue to flock to the border, which has overwhelmed agents and local law enforcement agencies. Many are fleeing crime and poverty in Central America, and most recently, Haiti.
At least 160,000 undocumented immigrants have been released into the United States with little to no supervision since March, according to Border Patrol documents.
Roma, Texas may be one of the busiest spots along the southern border for illegal crossing and cartel activity. Texas Republican Gov. Greg Abbott has deployed more Guard soldiers to the border in recent weeks for security as the Biden administration grapples with the surge.
Abbott, along with other GOP governors, has criticized Biden for creating a "humanitarian crisis" and chaos after rolling back the immigration policies of former President Trump.