Vice President Kamala Harris on Tuesday said she is "deeply troubled" by images from the border showing Border Patrol agents on horseback blocking migrants from entering the U.S. – the latest administration official to join the pile on against agents who are dealing with a colossal migrant surge in Del Rio.

"What I saw depicted about those individuals on horseback treating human beings the way they were, was horrible," Harris told reporters. "And I fully support what is happening right now, which is a thorough investigation into exactly what is going on there. But human beings should never be treated that way. And I'm deeply troubled about it. And I'll also be talking to Secretary [Alejandro] Mayorkas about it today."

Harris was reacting to images of Border Patrol agents in Del Rio, where thousands of Haitians have surged in recent days. Images showed agents on horseback blocking migrants from entering the U.S. and in one case grabbing onto a migrant’s shirt. 

Overwhelmed agents have been working six days a week, and more than 10 hours a day as they deal with the more than 14,000 mostly Haitian migrants that were at one time camped under the international bridge – with reports of tens of thousands more on the way.

As DHS has surged resources, including more agents on horseback, supplies and medical assistance, while also increasing deportation flights, the men and women in green have been attempting to stop migrants – who have traveled through multiple countries before arriving at the border – from coming into U.S. territory.

Some Democrats and media outlets falsely described the agents’ long reins, which they use to control their horses, as "whips." House Speaker Nancy Pelosi condemned what she described as "the inappropriate use of what appear to be whips by Border Patrol officers on horseback to intimidate migrants." 

Mayorkas and Border Patrol Chief Raul Ortiz both said on Monday that they did not see anything wrong with the images, and Mayorkas pointed out agents use long reins to control their horses, not whips, in difficult terrain. Ortiz also noted that agents don't know who are smugglers and who are migrants.

Ortiz said it is important that agents need maintain control of the horse to avoid injuries to both agents and migrants, and said working a horse in a riverine is a very difficult task. 

But the White House took a different view. Press Secretary Jen Psaki said: "I don't think anyone seeing that footage would think it was acceptable or appropriate."

By Tuesday morning, Mayorkas had changed his perspective.

"I was horrified by what I saw," Mayorkas told CNN. "I'm going to let the investigation run its course. But the pictures that I observed troubled me profoundly. That defies all of the values that we seek to instill in our people."