CBP investigating allegation by young girl that she was 'beaten and abused' at Clint border facility The government says the investigation into the March allegation is ongoing.

U.S. Customs and Border Protection is investigating allegations of physical abuse of a girl in its custody at a border facility in Clint, Texas, near the Mexico border, according to a government document provided to Congress.

The document says the girl reported on March 12 that she had been "beaten and abused" while in custody at the facility.

A CBP spokeswoman declined to provide details because she said the investigation remained open.

The Clint border facility, located outside El Paso, Texas, and across from Ciudad Juarez in Mexico, is at the center of allegations of child neglect by CBP's U.S. Border Patrol. Designated as a facility for "unaccompanied" minors -- many of them separated from extended relatives the government doesn't recognize as a legal guardian -- the Clint station quickly filled up at one point this spring with some 350 children, including toddlers and at least one infant.

Lawyers who inspected the facility said the children were denied showers, toothbrushes and cooked food, and older children were forced to care for the younger ones despite being unrelated. Trump administration officials said that while conditions were not ideal -- border patrol stations were never intended to house children -- they insisted that many of the allegations were overblown.

"The real story I would submit to you on the border crisis and our response is about our Border Patrol agents who have chosen a career about protecting others," acting Homeland Security Secretary Kevin McAleenan told reporters earlier this month.

An internal watchdog office has confirmed massive overcrowding and unsanitary conditions at other facilities, quoting one manager as saying his site was a "ticking time bomb."

The document alleging abuse by a female girl held at Clint was first reported by NBC News and was confirmed by ABC News.

At one point, some 2,500 migrant kids deemed "unaccompanied" piled up at these border facilities as the government scrambled to find beds for them in longer-term shelters at the Department of Health and Human Services.

In court records recently released, many of these children told court-appointed lawyers of spending weeks in freezing temperatures and claimed some border guards threatened them with prison if they tried to sneak any food from the facilities.

"I have not been told how long I have to stay here," a 5-year-old from Honduras told the lawyers. "I am frightened, scared and sad."

Others spoke about the freezing temperatures.

"It is always cold in the cage," a 17-year-old boy from Guatemala told the lawyers. "They took my (8-year-old) nephew's clothes when we arrived at Ursula because they were wet, and gave him a T-shirt, which is not enough to keep him warm."