The Border Network for Human Rights, an immigration and human rights advocacy group in in El Paso, Texas, issued a report Friday, describing cramped conditions and prolonged stays in detention amid a record surge of migrant families coming into the US from Central America, World News reported.
The report was based on dozens of testimonials of immigrants over the past month and a half.
It said some people at an encampment in El Paso are being forced to sleep on the bare ground during dust storms.
The report comes a day a teenage mother was found cradling a premature baby inside a US immigration processing center in Texas. An immigration advocate said the baby should have been in a hospital, not a facility where adults are kept in large fenced-in sections that critics describe as cages.
"The state of human rights in the US-Mexico borderlands is grave and is only getting worse," the immigrant rights group stated in its report, adding, "People are dying because of what is happening."
Five immigrant children have died since late last year after being detained by US border agents.
A professor who visited a a processing center in El Paso two weeks ago told the Associated Press that it resembled a "human dog poun".
Many of the complaints center on El Paso, where the US Department of Homeland Security's inspector general found severe overcrowding inside a processing center.
Migrants in El Paso and elsewhere also complained of inadequate food such as a single burrito and a cup of water per day. Women said they were denied feminine hygiene products.
Another complaint is that migrants are kept in detention beyond the 72-hour limit set by Customs and Border Protection. Some reported being held for 30 days or more, and one told The Associated Press she had been in detention for around 45 days.
The Trump administration has blamed the worsening crisis on inaction by the US Congress and Mexico.
A prominent US rights group says a plan by Trump's administration to make asylum seekers from Central America seek refuge in Guatemala instead of the United States would endanger refugees.
Human Rights First, which is based in New York City, reported on Friday it was "simply ludicrous" for Washington to assert that Guatemala was capable of protecting refugees from Honduras and El Salvador, when its own citizens are fleeing violence.