Women and children detained by US Customs and Border Protection (CBP) along the US-Mexico border are regularly held in freezing cells and suffer other harsh treatment, according to a new Human Rights Watch (HRW) report.

The report, entitled "In the Freezer: Abusive Conditions for Women and Children in US Immigration Holding Cells," was released on Wednesday and documents over 100 cases of immigrants being held beyond the three-day period recommended in CBP guidelines in frigid holding cells.

Often, the immigrants were only given mylar blankets, sheets made of heat-resistant plastic typically found in First Aid kits, for warmth. The cells were without bunks, mattresses or other amenities for sleeping.

"It was cold, really cold … There weren't any mats. We just slept on the floor," a Guatemalan woman identified as Carolina R told HRW.

Furthermore, CBP officers would often make women and children discard clothing down to a single layer.

"They didn't want me to keep both my blouse and my sweater. I had to pick one to keep, so I chose my sweater. They didn't explain why," Adela R, a woman who spent three nights in a holding cell with her infant child in Nogales, Arizona, said in the report.

The immigrants were held without access to showers. In some cases, the women detained were not given sanitary pads.

The report has prompted concerns by immigrant rights activists and groups.

Increased deaths, decreased apprehensions

According to Eddie Canalas, founder of the South Texas Human Rights Center (STHRC), which works to minimise migrant deaths on the Texas section of the US-Mexico border, the report highlights the troubling state of immigration policy in the US.

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"We're living through a very harsh police environment for immigrants in this country," Canalas told Al Jazeera.

"There's no space for humanity. There's no space for human rights."

Carlos Diaz, a CBP spokesman, said that the agency is has met HRW regarding the findings of its report.

"CBP operates short-term detention facilities, where individuals are generally held for 72 hours or less," Diaz said.

"CBP treats all individuals with dignity and respect, and ensures that all such facilities meet all relevant legal and policy requirements ... Additionally, both CBP's US Border Patrol and Office of Field Operations ensure that all agents and officers appropriately monitor the conditions in hold rooms, and enter pertinent information into the appropriate systems of record on a regular basis," he added.

Canalas said that detention in harsh conditions, as well as separation of parents and children, are being used to discourage undocumented immigrants from crossing into the US.

He added that such conditions also instil fear in immigrants.

"They go further underground, they're more vulnerable and more excludable," Canalas said.

This can lead to immigrants taking more dangerous routes to cross the border. The region's weather often drops below freezing in winter and is hot and dry in the summer.

STHRC, much like other immigrant rights groups on the border, sets up water stations for immigrants who risk dehydration in summer months.

Canalas noted that detentions have decreased, but deaths have increased.

According to the International Organisation of Migration, 412 immigrants died in 2017, up from 392 in 2016.

Immigrant apprehensions dropped 44 percent in the same period, from 611,689 in 2016 to 341,084 in 2017, according to US Department of Justice figures.

Canalas said that in Brook County, Texas, where STHRC operates, there have already been 13 known fatalities in 2018.

Sexual harassment

Women not only face cold, inhospitable holding cells, but also sexual harassment, according to a letter authored by 45 US Congressional representatives sent on Tuesday to the Department of Homeland Security, which oversees national immigration enforcement.

The letter said DHS must investigate allegations of sexual harassment against guards in the for-profit T Don Hutto immigration detainment centre in Texas put forward by Laura Monterrosa.

Monterrosa, a 23-year-old undocumented immigrant from El Salvador who was apprehended by ICE in May, claimed she was assaulted by a female guard in November. She has since attempted suicide and been placed in solitary confinement.

"Complaints of sexual abuse by guards and subsequent retaliation by ICE following victim grievances are disturbing and unacceptable," Congressman Lloyd Doggett said in the letter.

"No one should be subject to the appalling treatment that Laura has experienced while detained for nine months," Bob Libal, executive director at Grassroots Leadership, an immigrant advocacy organisation based in Texas, said in a statement delivered to Al Jazeera.

'Reasonable and comfortable'

The HRW report recommends that the CBP develop written guidelines to ensure further protections for women and children they detain.

These should include detaining "individuals overnight in holding cells only when it is unavoidable" and "develop written guidelines that ensure families are "not unnecessarily or intentionally separated".

Using these measures as a deterrent would be unlawful under international law, the report said.

Canalas said that until major changes are made in the US immigration policy, the system will remain "inhumane".

"How many times do we have to say it? The immigration policy of the US is completely broken," Canalas concluded.