(CN) – The overcrowded, unsanitary conditions inside detention facilities along the Rio Grande Valley in southwest Texas, where thousands of immigrants have been held past the maximum 72-hour holding period, are described as a “ticking time bomb” in a report released Tuesday by the Department of Homeland Security’s independent watchdog.

Photographs included in the report compiled by the department’s Office of Inspector General show dozens of immigrants, including children, cramped into jail-like cells or in chain link pens. Many are lying on the floor, huddled under silver Mylar blankets.

Another photograph shows 88 adult men crammed into a cell with a maximum capacity of 41 people. It is standing room only. When detainees noticed the inspector general observers, they pressed notes to the glass window and pointed to their beards, indicating how long they had been in custody, according to the report.

The photographs were taken by observers from the Office of Inspector General during a series of unannounced inspections in June at five detention facilities and two ports of entry along the U.S.-Mexico border.

The inspectors discovered a pattern of “dangerous” overcrowding and prolonged detentions, and said in the 16-page report that the Department of Homeland Security must immediately address these issues to comply with legal standards.

At the time of the inspections, Border Patrol was holding approximately 8,000 detainees in custody, 3,400 of which were held past the 72-hour holding period generally allowed under Transport, Escort, Detention and Search (TEDS) standards and required under the Flores Agreement. Of those 3,400 migrants, 1,500 had been held longer than 10 days.

The inspector general identified 1,031 unaccompanied minors at the Centralized Processing Center in McAllen, Texas, and 806 had completed processing – 165 of whom had been at the McAllen facility for over a week. More than 50 unaccompanied minors were younger than seven years old, and some had been in custody for more than two weeks.

In addition to overcrowding, the inspector general reported clothing shortages, unhygienic conditions and a lack of hot meals at the facilities.

“While all facilities had infant formula, diapers, baby wipes and juice and snacks for children, we observed that two facilities had not provided children access to hot meals – as required by the TEDS standards – until the week we arrived,” the report states.

Many migrants only received bologna sandwiches, causing constipation, which, in some cases, required medical attention.

The inspector general also discovered that some adults at the migrant camps had not been provided access to a shower despite being detained for as long as a month.

“At some facilities, Border Patrol was giving detainees wet-wipes to maintain personal hygiene. Most single adult detainees were wearing the clothes they arrived in days, weeks and even up to a month prior,” the report states.

The inspector general attributed the overcrowding to a bottleneck: Many immigrants had completed initial processing and were ready to be transferred to other facilities, but Border Patrol could not release them until Immigration and Customs Enforcement (ICE) has space for single adults and families and the Health and Human Services Department (HHS) has space for unaccompanied minors.

Both departments are “operating at or above capacity,” according to the report.

The conditions described in the report are in line with what members of Congress reported observing on a tour of immigrant detention facilities Monday.

Representative Alexandria Ocasio-Cortez, D-New York, said a woman being held at one facility described the treatment she was experiencing as “psychological warfare.”

Ocasio-Cortez also reported some migrants being forced to drink straight from the toilet bowl inside their holding cells. Although the toilets were outfitted with sinks atop the water tanks, she said there was only one toilet available at the facility she visited, and the sink portion did not function.

“[T]he women were told they could drink out of the bowl,” Ocasio-Cortez wrote on Twitter Monday.

Representative Madeleine Dean, D-Penn, said she encountered 15 women over the age of 50 sleeping in a “small concrete cell” with no running water and that they had gone weeks without showers.

Brian Hastings, chief of operations for the Border Patrol, denied accusations that migrants were forced to drink from toilet bowls at the facilities and balked at lawmakers’ portrayals of the conditions in an interview with CNN .

In a Senate Homeland Security Committee hearing June 26, Hastings said that immigrant detention facilities were properly stocked, and that “a lot of our stations look like Costco.”

The inspector general concluded that it is concerned that the Department of Homeland Security is “not taking sufficient measures to address the prolonged detention” of single adults in Border Patrol custody.

In its response to the inspector general’s report, which is also known as the “Draft Management Alert,” the Department of Homeland Security said that border patrol is doing “everything it can to promptly transfer, transport, process, release, or repatriate those in our custody.”

“However, without Congressional action to address legal and judicial loopholes, families and [unaccompanied minors] will continue to be incentivized by the smuggling organizations to make the dangerous journey and be encouraged by the likelihood that families will not be detained during their immigration proceedings,” the response states. “As more migrants become emboldened by these loopholes, [U.S. Customs and Border Patrol] expects this influx to not only continue, but also to escalate.”