“The individuals who are the subject of the investigation are on administrative duties currently,” Mr Mayorkas tweeted. “They are not executing their other law enforcement duties and they are not to be interacting with other migrants at this time during the pendency of the investigation.”
Shocking photos and videos emerged earlier this week from Del Rio, Texas, where thousands of Haitian refugees have arrived seeking asylum. In disturbing footage by Al Jazeera and Reuters, border officials on horseback appeared to use reins or whips to forcefully drive them back.
On Tuesday, Mr Mayorkas condemned those tactics and said they would be investigated.
“We do not condone, we do not tolerate any mistreatment of any migrant,” Mr Mayorkas wrote. “The actions we’re taking are swift and strong, and we will take further action as the facts adduced in the investigation compel.”
Vice President Kamala Harris has also denounced the violence.
“What I saw depicted about those individuals on horseback, treating human beings the way they were, is horrible,” Ms Harris said on Tuesday. “Human beings should never be treated that way and I am deeply troubled by it and I’ll also be talking with Secretary Mayorkas later today about it.”
One police union, meanwhile, has defended the Border Patrol officers, arguing that they were using reins, not whips.
“For all you Twitter warriors out there: these are NOT whips. And no, Border Patrol agents are NOT ‘whipping’ people,” wrote the National Fraternal Order of Police. “They are REINS... Stay with us here, like a steering wheel is used to drive a car, the reins are used to ‘drive’ the horse.”
Tensions have been high along the US-Mexico border, where more than 12,000 migrants, many of them Haitians, have set up a makeshift refugee camp as they flee their home country’s disintegrating political situation and seek asylum.
On Sunday, the US began flying migrants out of the camps on flights back to the Haitian capital Port-au-Prince, where the country has been reeling after a massive earthquake in August and the assassination of its president in July.
“What kills me about that is that everyone knows what we Haitians are going through,” one man told an Al Jazeera film crew. “There’s no president. Crime is high. Students can’t go to school. There’s no work. The economy is down. People can’t put up with that. Deportation is not good for us.”