McALLEN, Texas (Border Report) — Backpacks loaded with ammo and a homemade explosive device were discovered by U.S. Border Patrol agents along the South Texas border wall in Starr County, said officials who are conducting sweeps of the river north and south coordinating with Mexican authorities.

U.S. Customs and Border Protection on Friday said Border Patrol agents “discovered an abandoned bag containing a potential homemade explosive” on Sept. 5, near the border in Fronton, Texas.

Border Patrol agents found a homemade explosive on Sept. 5 near Fronton, Texas, and McAllen police hauled it away and safely detonated it, CBP said Friday. (CBP Photos)

Agents coordinated with law enforcement from the Bureau of Alcohol, Tobacco, Firearms and Explosives, along with McAllen police, which took the device away and detonated it.

They “classified it as a ‘noise maker’ as it contained flash powder,” according to a CBP statement Friday.

Flash powder was found inside the backpack but “no fragmentation to cause major injuries or casualties,” CBP said.

“A dangerous situation was averted in our border area,” Rio Grande Valley Border Patrol Chief Patrol Agent Gloria Chavez posted on X, the platform formerly Twitter.

Chavez said the backpacks full of ammunition and the rudimentary explosive device were “an example of the tactics & weapons that criminals employ against our agents.”

She also thanked “McAllen PD for assisting in safely detonating this homemade explosive!”

U.S. Sen. John Cornyn, a Republican from Texas, also is aware of the incident, his office said Friday.

“Sen. Cornyn is aware of that discovery made by the Border Patrol,” a Cornyn spokesperson told Border Report.

Sens. Cornyn and Ted Cruz, both Republicans from Texas, on Oct. 27 toured the border and the Rio Grande Valley Sector along with Sens. Mike Lee, of Utah, and Pete Ricketts, of Nebraska.

U.S. Border Patrol watch Mexican law enforcement sweep the southern side of the Rio Grande in coordinated sweeps conducted Oct. 31. (CBP Photos)

Chavez this week also tweeted that on Tuesday in Harlingen, U.S. Border Patrol agents conducted sweeps along the Rio Grande while “Mexican officials conducted border security operations simultaneously & patrolled each side of the Rio Grande River” in Tamaulipas, Mexico.

U.S. Border Patrol agents patrol the Rio Grande near Harlingen, Texas, on Oct. 31, 2023, while Mexican law enforcement patrol south of the river in what is called ‘mirrored patrols.’ (CBP Photo)

Photos she posted show against working parallel of the river on both sides in what she called “mirrored patrols” that she said “are very effective in increasing detection, safety, and security in these sections of the border.”

Sandra Sanchez can be reached at