Still, Biden added that he ultimately bears responsibility for the situation at the Texas border with Mexico amid an influx of thousands of Haitians that has drawn international attention after viral photos showing agents on horseback using reins against the migrants.

“Of course, I take responsibility. I’m president,” he told reporters at the White House.

“I promise you those people will pay,” he added of the agents. “It’s simply not who we are.”

US Homeland Security Secretary Alejandro Mayorkas, who is scheduled to speak at a White House news briefing later on Friday, has launched an investigation over the issue.

Despite the widespread outrage stirred up by the border guard images, pressure is also growing on Biden to tighten the border.

Meanwhile, Mexico is urging Haitians at the border to give up and return to Mexico’s frontier with Guatemala to request asylum.