McALLEN, Texas (Border Report) — U.S. Border Patrol agents working along the Rio Grande in South Texas were fired upon from Mexico on Monday.

The agents were arresting migrants in Fronton, Texas, in rural Starr County, when shots were fired at them from Mexico, a spokesperson for U.S. Customs and Border Protection told Border Report

“Shots were fired from Mexico in the direction of Border Patrol agents during the apprehension of migrants in the area adjacent to the Rio Grande.  No one was injured in the incident and shots were not returned,” the spokesperson said.

This section of Starr County is where the most drug apprehensions are made along the Texas-Mexico border.

Several “islands” or landmasses of silt that have sprung up in the river allow drug traffickers to cross midway and haul loads of drugs or smuggle migrants into the country.

This area also is where a section of a 30-foot-tall border wall was built during the Trump administration — one of the first segments to be built in Starr County.

A U.S. Border Patrol agent stands Jan. 9, 2020, near a newly built 30-foot-tall border wall in Fronton, Texas in Starr County. (Sandra Sanchez/Border Report File Photo)

Monday’s incident is being reviewed by the FBI and CBP’s Office of Professional Responsibility.

Sandra Sanchez can be reached at