The U.S. Customs and Borders Agency allowed reporters and Democratic lawmakers inside a detention centre in the state of Texas which has created a storm of outrage over a new U.S. government policy of separating migrant children from their parents.

The lawmakers came to south Texas, they say, to learn more about the agency's processing of undocumented immigrants entering the United States, including a Trump administration policy to refer all people who cross the border illegally for criminal prosecution on top of immigration proceedings. As a result of enforcing that policy, families who cross illegally have been separated from their children because those accompanying the children are put into the criminal justice system.

The Texas facility is known as Ursula, though immigrants are reportedly calling it La Perrera - dog kennel in Spanish - in reference to the cages used to hold children and adults who have ended up there after crossing the border from Mexico illegally.

The warehouse-like facility has holding pens made from chain-link fences on the inside separating the immigrants. Mattresses with thermal blankets were strewn on the floors.

"One cage had 20 children inside. Scattered about are bottles of water, bags of chips [crisps] and large foil sheets intended to serve as blankets," the Associated Press reports.

Democratic Senator Jeff Merkley led the team of lawmakers to the site in the town of McAllen on Sunday. He hit the headlines earlier this month when he was turned away from another facility housing some 1,500 boys in a disused Walmart store.

Speaking to CNN after the visit to Ursula, he said: "In wire-mesh, chain linked cages that are about 30x30 [feet], a lot of young folks put into them. "I must say though, far fewer than I was here two weeks ago. I was told that buses full (of children) were taken away before I arrived.”

US Customs and Border Patrol released the pictures from McAllen, Texas Illegal Immigrant detention facility. (Photo: US Customs and Border Agency)

Inside Ursula, more than 1,100 illegal immigrants are waiting to be processed. They have been separated into three wings: unaccompanied children, lone adults and parents with their children. Officials said nearly 200 of those being held there were unaccompanied minors and another 500 were parents with their children.

Customs and Border Patrol released the below pictures from McAllen, Texas detention facility. (Photo: US Customs and Border Agency)

In another town of Brownsville, Texas some 1,500 boys are being housed inside a building that was once a Walmart store. The boys, aged 10 to 17, were all caught illegally crossing the border. It is America's largest facility for such minors, and numbers have increased in the past month by several hundred.

The BBC spoke to an activist Anne Chandler, who's running a non-profit project for migrant children found on the southern U.S. border, told Texas Monthly she had heard stories of "kids that are very young, that are breastfeeding babies and under three in the shelters, separated from their parents".

The head of the Tahirih Justice Centre in Houston said she had seen cases where parents had not been told ahead of time that their child was being taken away, and instead were told by immigration officers that their child required a bath, only to not be returned. "I was talking to one mother, and she said, "Don't take my child away," and the child started screaming and vomiting and crying hysterically, and she asked the officers, "Can I at least have five minutes to console her?" They said no," Ms. Chandler told the magazine.

(The above story first appeared on LatestLY on Jun 19, 2018 03:06 AM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).