The head of the United States Border Patrol said sexist posts and comments mocking migrant deaths in a closed Facebook group for agents and employees are "completely inappropriate" after a ProPublica investigation into the group. ProPublica is an independent, US-based investigative news website.
Carla Provost said in a statement on Monday that any employee who violated standards will be held accountable.
ProPublica published a report on Monday on the group that comprises about 9,500 current and former employees. There are about 20,000 active Border Patrol agents.
Group members posted graphic doctored images of US Representative Alexandria Ocasio-Cortez, a New York Democrat. Other posts refer to Ocasio-Cortez and Representative Veronica Escobar, of Texas, in sexually explicit ways. One member encouraged agents to throw burritos at them during a facility tour on Monday.
After leaving an El Paso facility, Ocasio-Cortez wrote in a tweet, "I see why CBP officers were being so physically & sexually threatening towards me," an apparent reference to the Facebook group.
Other posts in the group included jokes about the deaths of migrants, according to ProPublica.
The non-profit news organisation said one member posted a GIF of Elmo, a character on the popular children's programme Sesame Street, with a quote that read "oh well" in an exchange about 16-year-old Guatemalan Carlos Gregorio Hernandez Vasquez, a Guatemalan migrant, who died in May while in custody at a Border Patrol station in Texas.
The assistant commissioner of the office of professional responsibility said the "disturbing social media activity" was being investigated.
Migrant detention conditions
The report comes amid outrage over the conditions at several migrant detention centres along the border.
US politicians, including Ocasio-Cortez, who visited two Texas centres on Monday described "horrifying" conditions.
The politicians said that migrants told them they experienced psychological abuse and were told to drink out of toilets.
"After I forced myself into a cell w/ women&began speaking to them, one of them described their treatment at the hands of officers as "psychological warfare," Ocasio-Cortez tweeted. "This has been horrifying so far."
Customs and Border Protection (CBP) has not responded to the politicians' comments.
Conditions at US facilities holding migrants along the US-Mexico border have become a flashpoint in recent weeks after an internal government watchdog warned of "dangerous overcrowding" at the El Paso facility in May. In June, immigration lawyers raised alarms over squalid conditions facing hundreds of children at another facility in Clint, Texas. Politicians visited both facilities on Monday.
At a news conference on Friday, acting Homeland Security Secretary Kevin McAleenan denied the lawyers' allegations and defended operations at the Clint facility. McAleenan said that the reports regarding the Clint centre were "unsubstantiated".
The US Congress last week passed a $4.6bn aid package to address a migrant surge at the US-Mexico border as a wave of Central Americans seek to reach the US.
Some Democrats in the US House of Representatives had pushed for the legislation to include additional protections for migrant children, but the bill ultimately passed without them.
President Donald Trump has controversially made cracking down on immigration a cornerstone of his administration.