Following a visit to a migrant detention center in Texas on Monday, the New York congresswoman Alexandria Ocasio-Cortez called conditions “horrifying” and denounced sexualized threats against her – allegedly made by Customs and Border Protection (CBP) officers – in the lead-up to the visit.

Ocasio-Cortez and Democratic colleagues were en route to a facility in Clint, Texas, when ProPublica revealed the existence of a secret Facebook group, branded as a forum for CBP officers, with 9,500 members, some of whom ProPublica linked to public Facebook pages for verified officers.

Posts in the Facebook group included one that encouraged officers to throw a “burrito at these bitches”, one saying “Fuck the hoes”, one saying “There should be no photo ops for these scum buckets”, and one depicting Ocasio-Cortez engaged in oral sex at a detention center. Another post questioned the veracity of a recently published photo of a drowned father and daughter in the Rio Grande.

“9,500 CBP officers sharing memes about dead migrants and discussing violence and sexual misconduct towards members of Congress,” Ocasio-Cortez tweeted in reaction to the report. “How on earth can CBP’s culture be trusted to care for refugees humanely? PS I have no plans to change my itinerary & will visit the CBP station today.”

What Ocasio-Cortez saw inside the facility, which has been plagued by recent reports of abusive treatment of detained children, was “horrifying”, she tweeted.

She reported officers forcing women to drink out of toilets:

Just left the 1st CBP facility.



I see why CBP officers were being so physically &sexually threatening towards me.



Officers were keeping women in cells w/ no water & had told them to drink out of the toilets.



This was them on their GOOD behavior in front of members of Congress. — Alexandria Ocasio-Cortez (@AOC) July 1, 2019

Ocasio-Cortez said she saw officers making light of conditions inside the facility:

Now I’ve seen the inside of these facilities.



It’s not just the kids. It’s everyone. People drinking out of toilets, officers laughing in front of members Congress.



I brought it up to their superiors. They said “officers are under stress & act out sometimes.” No accountability. — Alexandria Ocasio-Cortez (@AOC) July 1, 2019

She said detainees told her officers were abusing them:

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” - waking them at odd hours for no reason, calling them wh*res, etc.



Tell me what about that is due to a “lack of funding?” — Alexandria Ocasio-Cortez (@AOC) July 1, 2019

With serial visits by Democratic presidential candidates and elected officials to migrant detention centers in recent days, the Trump administration has forcefully rejected claims of systemic abuse of detainees, calling them “unsubstantiated”.

Late on Monday, the US Immigration and Customs Enforcement agency (Ice) confirmed the death in their custody of a 30-year-old Honduran man, Yimi Alexis Balderramos-Torres, marking the sixth person to die in ICE custody since October 2018. The death was first reported by BuzzFeed News.

Democratic congressman Joaquin Castro, who also visited the centers, tweeted footage of a crowded cell, writing that some detainees had been separated from their children:

This moment captures what it’s like for women in CBP custody to share a cramped cell—some held for 50 days—for them to be denied showers for up to 15 days and life-saving medication. For some, it also means being separated from their children. This is El Paso Border Station #1. pic.twitter.com/OmCAlGxDt8 — Joaquin Castro (@JoaquinCastrotx) July 1, 2019

As Ocasio-Cortez visited the Texas facility, NBC News revealed an internal Department of Homeland Security report that said conditions inside an El Paso center were so dire that as early as May, border agents were arming themselves against possible riots.

Inspectors at the facility noted “only four showers were available for 756 immigrants, more than half of the immigrants were being held outside, and immigrants inside were being kept in cells maxed out at more than five times their capacity”, NBC reported.

“A cell meant for a maximum of 35 held 155 adult males with only one toilet and sink. The cell was so crowded the men could not lie down to sleep,” the report went on. “With limited access to showers and clean clothing, detainees were wearing soiled clothing for days or weeks.”

The Department of Homeland Security did not reply to a request for comment.

At a news conference last week, the homeland security secretary, Kevin McAleenan, assured the public that the detention centers were “clean and well managed”, despite a legal report that documented children inside the centers given insufficient food and wearing soiled clothing and diapers.

“All of this received relatively little attention and little action until this past week on the Hill,” McAleenan said. “But unsubstantiated allegations regarding a single border patrol facility in Clint station in Texas created a sensation.”

However, the California congresswoman Judy Chu, also on the trip with Ocasio-Cortez, said she met a woman who had been told by a border agent: “If you want water, just drink from a toilet.”

“These are the same CBP personnel who threatened to throw burritos at members of Congress,” Chu tweeted. “Changes must be made.”

Ocasio-Cortez tweeted that migrants were being treated “like animals”.

She wrote: “This has been horrifying so far. It is hard to understate the enormity of the problem. We’re talking systemic cruelty [with] a dehumanizing culture that treats them like animals.”