(CNN) Pediatricians who have volunteered to work with migrants in El Paso, Texas, are walled off from any contact with "whoever is providing the medical care to these individuals" in government run migrant detention centers, pediatrician Dr. Carlos Gutierrez said Tuesday.

"That is not medical care. That's malpractice," said Gutierrez, who has helped treat families received by Annunciation House, a nonprofit that runs temporary residential centers that receives migrants released by US Immigration and Customs Enforcement or US Customs and Border Protection.

During a press conference on Tuesday in El Paso, the doctors said they know of dozens of additional doctors that would like to provide care, but the centers aren't allowing any of them in, as they have in the past.

The doctors said migrants report that agents take away their medicines that the migrants lacked proper nutrition.

They "describe a situation no human being should have to go through," said Gutierrez. "This is coming through the mouths of the refugees," not through media reports, he added.

Roughly six to seven weeks ago, Annunciation House was receiving between 600 and 1,000 migrants per day, according to Ruben Garcia, the organization's director. Now, it's about 100 per day -- sometimes less.

"I keep hearing that CBP facilities are overwhelmed ... and we are not seeing that," Garcia said Tuesday.

Acting Homeland Security Secretary Kevin McAleenan said Friday that it appears there will be a 25% decrease in June in the numbers of migrants crossing at the US-Mexico border, for which McAleenan credited Trump administration initiatives

Pediatrician Dr. Jose Manuel De la Rosa said that among migrant children seen recently, they're treating problems typical of any children.

There are "no exotic diseases being seen," he said. "We see runny noses and runny bottoms. We see chickenpox, we see other childhood diseases."

In 2014, the doctors said they had access to the government facilities that were clean and well managed at the time, but De la Rosa said CBP has told them this time that "it is not current policy."

That's left Gutierrez "upset" and "angry."

"I don't think they get any of the care," Gutierrez said.

When the children are released, the doctors have no idea what kind of treatment they have had. US agencies told the doctors that they want to "respect the privacy of the refugee." But, Gutierrez said a lack of continuity of care "is piss-poor medical care."

Gutierrez said he has been deeply upset by the government centers' practice of taking away medicines that migrants arrive with, and medicines are not given back when they're released.

Overcrowding at these facilities has also been a public health problem, the doctors said. Dr. Blanca Garcia described seeing a boy about two months ago with a high fever who was eventually hospitalized.

"How could nobody have noticed that this child was so sick?" she asked. "When you have so many people in custody, I'm sure that it's easy to miss something like that.

"Unfortunately, that's how tragedies happen," she said.

Dr. Lisa Ayoub-Rodriguez said she has treated patients who haven't received "basic human needs" inside the facilities. One mother complained that she couldn't keep her child warm with the onesie and plastic blanket she was given.

"Despite her best efforts, her little newborn's fingers and toes were still blue," she said.

The mother's milk supply had dropped and she was dehydrated, Ayoub-Rodriguez said. The doctor asked if she had been given water or had asked for water and the woman told her no.

"I see this often in the population, they are afraid to ask for help," Ayoub-Rodriguez said. "This is a basic example, a very simple case of a family not receiving basic human needs, access to water and warmth. This is why children should not be in a detention centers."

Asked about the government's practice of taking medicines away and if they would allow doctors into the facilities in the future, CBP spokesperson Roger Maier said in an emailed statement:

"Our facilities are secured locations, where the employees and contractors are thoroughly vetted before they are allowed to interact with anyone in our custody. We have [US Department of Homeland Security] personnel and contracted medical staff at several locations throughout our sector who perform initial screenings and provide medical treatment when required. If the determination is made that anyone our custody needs additional medical attention, we will transport them to a local hospital where they receive the necessary attention."

At least six children have died in US custody

around El Paso. Since September, at least six migrant children have died in federal custody, including three that were taken into custodyaround El Paso.

In June , a team of doctors, lawyers and advocates warned that there were major health and hygiene problems at several US Customs and Border Protection facilities in Texas.

Many of the children lived in what they called "deplorable conditions" and didn't have access to soap to wash their hands or toothbrushes to brush their teeth, according to a legal filing in federal court in which a group of lawyers asked a judge to hold the Trump administration in contempt and to order the immediate improvements to conditions at US facilities where children are being held.

According to the filing, some of the children said they hadn't showered in weeks. They lacked access to adequate nutrition, stayed in cold facilities and slept on the floor.

The team had visited the children because it is monitoring the government's compliance with the law.

An agreement gives children the right to "safe and sanitary conditions of detention." The Flores Agreement, as the 1997 settlement is known, also requires the government to release children from immigration detention without unnecessary delay to their parents, other adults or licensed programs. It's a settlement that the Trump administration has been pushing to end, calling it burdensome.

In addition to a lack of "basic hygiene," cases of flu were reported and lice was an issue. Medical screenings have been criticized as "inadequate."

Last month , a federal judge ordered US Customs and Border Protection to urgently permit health experts into detention facilities holding migrant children to ensure they're "safe and sanitary" and assess the childrens' medical needs.

US District Judge Dolly Gee set a deadline of July 12 for the parties to "file a joint status report regarding their mediation efforts and what has been done to address post haste the conditions described."

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The American Academy of Pediatrics has long had an opinion that "children should not be in detention centers," pediatrician De la Rosa said on Tuesday.

"These are not little adults," he said, adding that children need a trained eye to handle their medical conditions.

"This is life and death," Ayoub-Rodriguez said.