(CNN) Photos obtained exclusively by CNN show migrants at the McAllen, Texas, Border Patrol station over the weekend, many of whom are children, sleeping on the ground on rocks and covered by Mylar blankets.

A baby bottle filled with milk can be seen in one photo next to a child sleeping outside on dirt, and in another, a woman is seen sitting on rocks leaning against a wall clutching a child.

In others, migrants are seen seemingly wandering the premises, which has four temporary tents to accommodate the swell of migrants approaching the US-Mexico border. One photo shows an agent holding a megaphone in a sea of migrants outside of the station.

The photos came from a source who has access to the facility and was disturbed by the conditions over the weekend. Customs and Border Protection has confirmed the images are of the McAllen border station.

"Nobody, no matter who you are, where you are from should spend an hour like this. This is the United States of America. Not in our country," the source, who has seen the conditions firsthand, said.

An official from the Department of Homeland Security, which oversees Customs and Border Protection, responded to the photos in a statement saying in part: "As multiple DHS officials have been warning for months, the border security and humanitarian crisis continues to worsen. Current facilities and funding are inadequate for migrant flows." The official cited the administration's request for additional resources to house migrants, and legislative changes to stem the flow of migrants.

"Again, Border Patrol agents are doing everything they can to protect and care for migrants in their temporary custody. Border Patrol stations are simply not equipped to handle the number of families and children arriving along the southwest border, and we need Congress to act to provide immediate relief," the official said.

Photos: See conditions at McAllen Border Patrol station Border Patrol station in McAllen, Texas, in May 2019. Provided by source to CNN. Hide Caption 1 of 7 Photos: See conditions at McAllen Border Patrol station Border Patrol station in McAllen, Texas, in May 2019. Provided by source to CNN. Hide Caption 2 of 7 Photos: See conditions at McAllen Border Patrol station Border Patrol station in McAllen, Texas, in May 2019. Provided by source to CNN. Hide Caption 3 of 7 Photos: See conditions at McAllen Border Patrol station Border Patrol station in McAllen, Texas, in May 2019. Provided by source to CNN. Hide Caption 4 of 7 Photos: See conditions at McAllen Border Patrol station Border Patrol station in McAllen, Texas, in May 2019. Provided by source to CNN. Hide Caption 5 of 7 Photos: See conditions at McAllen Border Patrol station Border Patrol station in McAllen, Texas, in May 2019. Provided by source to CNN. Hide Caption 6 of 7 Photos: See conditions at McAllen Border Patrol station Border Patrol station in McAllen, Texas, in May 2019. Provided by source to CNN. Hide Caption 7 of 7

The White House has asked for an additional $4.5 billion this year to pay for humanitarian assistance, border operations and things like additional personnel, to address the rising number of migrants at the border.

The McAllen station is one of nine stations in the Rio Grande Valley -- along with a central processing center.

It also is frequently visited by elected officials, including President Donald Trump. During his visit in January, Trump met with Border Patrol agents and participated in a roundtable discussion flanked by then-Homeland Security Secretary Kirstjen Nielsen where he pledged the construction of a "powerful steel barrier."

But Trump's promised border wall and aggressive immigration policies have so far provided little reprieve.

President Donald Trump after his visit to US Border Patrol McAllen Station in McAllen, Texas, on January 10, 2019 (Photo by Jim WATSON / AFP)

In April alone, the Border Patrol arrested 98,977 migrants for illegal entry, many of whom were families -- an increase from March. And over the weekend, apprehensions of migrants at the southern border surpassed 500,000 for the fiscal year so far, already easily exceeding the total for fiscal year 2018, which was nearly 400,000, according to a Border Patrol official.

For children, including many who have already walked hundreds of miles to get to McAllen, the Border Patrol act as a lifeline - especially in the coming months when temperatures in the Rio Grande Valley can reach upwards of 100 degrees.

'The flow is coming faster, frankly, than we can process it'

Border Patrol stations are designed to intake and process migrants who cross the border illegally. But stations have been stressed with overcrowding. When agents get backlogged with processing, indoor holding areas get full, forcing people to wait outside.

On Saturday, Acting Homeland Security Secretary Kevin McAleenan visited McAllen, Texas, with Acting Department of Defense Secretary Patrick Shanahan to visit the same station where the photos were taken. DHS has sought the assistance of the Pentagon to address the situation at the border.

"Our apprehension numbers are off the charts compared to recent years," Border Patrol Chief Carla Provost told lawmakers last week. "The number of family units and unaccompanied children has skyrocketed to 64 percent of southern border apprehensions."

For months, CBP, has been raising the alarm as it faces more families and children coming across the border -- a shift from previous years when single adult males made up a large number of border apprehensions. Overcapacity at facilities has led to scenes like the ones illustrated in the photos.

With the constant flow of migrants, it's become increasingly difficult for CBP to process and transfer migrants fast enough to make room for new people being arrested crossing the border illegally.

"The flow is coming faster, frankly, than we can process it," a Border Patrol official, who asked not to be identified, told CNN.

Earlier this year, McAleenan, then-CBP commissioner, said he was moving 750 officers from "key roles" at the ports of entry to help Border Patrol care for migrants, including helping with processing and transportation, adding that the shift would cause a slowdown in trade and an increased wait for cars and pedestrians crossing legally.

In an attempt to remedy the strain on agents, the Border Patrol, with the help of Immigrations and Customs Enforcement, have started flying some migrant families from the Rio Grande Valley to Del Rio, Texas, to be processed. A flight is scheduled daily to take around 135 people to Del Rio, according to the official. This, in addition to the multiple busloads of families per day that are being taken up to Laredo for processing.

The need for more shelters has become clear as facilities reach capacity. In late March, for example, another facility in McAllen was over capacity. The facility, designed to hold 1,500, was crammed with 2,200 migrants detained at the border. That's nearly double the number who were there last summer.

The goal is to move people out of the processing center and other Border Patrol facilities within 72 hours, but that doesn't always happen. And in some cases, CBP has had to release migrants -- a practice Trump has derided as "catch and release." Since March 19, 40,000 families, who have been processed and deemed non-criminal, have been released with a court date, the Border Patrol official told CNN.

Since assuming the role of acting Homeland Security secretary last month, McAleenan has appeared before lawmakers on the Hill and testified about DHS's strained resources and the need for funds to address the humanitarian and border security crisis.

"The new waves of vulnerable populations arriving here and exacerbating the already urgent humanitarian security crisis at the border," McAleenan told a House appropriations subcommittee late last month. "We don't have room to hold them, we don't have the authority to remove them fairly and expeditiously, and we are not likely -- and they are not likely to be allowed to remain in the country at the end of their immigration proceedings. The status quo is not acceptable."

The $4.5 billion funding request is one of several actions happening simultaneously to address the border situation and the nation's immigration system more broadly. White House senior adviser Jared Kushner has been working on a plan to overhaul the US immigration system and is slated to brief Republican senators on it at their Tuesday lunch. Meanwhile, Sen. Lindsey Graham, R-South Carolina, is set to unveil legislation proposing changes to the asylum process on Wednesday.

Each of these actions are sure to receive objections from Democrats -- who, in some cases, have already denounced the request for additional funds, pointing the blame at the administration's immigration policies -- leaving the White House and the Hill in a stalemate as the number of apprehensions continue to rise.