Department of Homeland Security Secretary Alejandro Mayorkas and Border Patrol Chief Raul Ortiz said they would look into agents on horseback using their horses and what officials describe as the horse reins to push back migrants at the river between Ciudad Acuña, Mexico, and Del Rio, Texas, where thousands of migrants remain camped around a bridge.
The images have drawn rebuke from Democratic members of congress and White House Press Secretary Jen Psaki called it "horrific," but was looking to gather more information.
Reuters reports at least one mounted officer was seen "unfurling a cord resembling a lariat, which he swung near a migrant's face."
A photographer for the El Paso Times took photos of the agents on horseback with the captions "U.S. Border Patrol agents deter Haitians from returning to the U.S. on the bank of the Rio Grande after migrants crossed back to Mexico for food and water."
A social media video also showed the scene at the border, with agents on horseback apparently trying to keep migrants from making it to shore after crossing the river into the U.S.
Mayorkas and Ortiz said they saw nothing apparently wrong based on the widely seen photos and video. Ortiz said he would investigate to make sure there were no “unacceptable” actions by the agents.
Later Monday, the Department of Homeland Security issued a statement calling the footage “extremely troubling” and promising a full investigation that would “define the appropriate disciplinary actions to be taken.”
Critics have claimed the agents were using whips. Mayorkas said agents use long reins, not whips, to control their horses, a stance reiterated by Jon Anfinsen, Local President of the Border Patrol union in Del Rio Sector. He said the reins are used both as a way to control the horses but also to keep people from getting too close.
"To protect people on the ground, they must keep them away from the horses because if a horse steps on someone, the person could get a broken leg or other injury," Anfinsen said. "If agents lose control of their horses, agents and immigrants can get hurt."
Psaki called the images "horrible." She added that while she didn't have full context. "I can't imagine what context would make that appropriate, but I don't have additional details."
When pressed on whether the agents involved should be fired, Psaki said, "Of course they should never be able to do it again. I don't know what the circumstances would be. It's obviously horrific, the footage." But she said she would need to get more information.
Ortiz, the former chief of the Del Rio sector, said it can be confusing to distinguish between migrants and smugglers as people move back and forth near the river.
The Associated Press contributed to this report.