"We're going the absolute wrong direction," one lawmaker said.
As U.S. authorities grapple with historically high levels of unauthorized migration from around the world, the border apparatus has been pushed into overdrive, drawing the concern of politicians, advocates and law enforcement alike.
Administration officials say they face an "unprecedented" level of displaced people from across the Western Hemisphere who want to come to the U.S.
Experts have described these "push factors" as primarily driven by poor economic conditions in Central and South America, natural disasters fueled by climate change as well as a general lack of security, according to the Congressional Research Service.
The numbers are record-breaking: The Border Patrol made about 10,500 apprehensions along the southwest border on Tuesday, according to two sources familiar with the data. Agents made roughly 10,600 migrant apprehensions along the southwest border on Wednesday.
That was only a slight decline from Monday, and still high.
One source said about 1,600 migrants were stopped at ports of entry and about 11,000 were apprehended on Monday.
The numbers this week represent daily highs not seen since at least the early 2000s, according to one source.
Over the past week, Border Patrol agents have made an average of 9,559 apprehensions per day, according to internal U.S. Customs and Border Protection (CBP) data.
And while the total number of Border Patrol apprehensions in the southwest decreased slightly from October 2022 to October 2023, it remains high compared to 2019.
Overall, the U.S. immigration system "really isn't even built for half" of the migrants seen crossing the border today, a senior CBP official told ABC News. A law enforcement source said that the holidays play a factor as well.
The system beyond the border is complicated by limited capacity and backlogs with immigration courts and detention centers. U.S. immigration courts recently hit a record-breaking case backlog of 3 million, according to researchers at Syracuse University.
"The cost of this is going to spread out through society, no question," Sam Schultz, a volunteer who works to provide basic necessities to the migrants once they arrive, recently told ABC News. "There's just no way that you can deal with an influx of people like this without being a cost to society."
Rep. Tony Gonzales, a Republican whose district encompasses much of Texas' border with Mexico, told reporters on Wednesday that the system needed a significant boost in funding and resources -- including to ensure national security, limit the spread of drugs and provide more judges to rule on migrants' cases, like those seeking asylum.
Hospitals and holding facilities were full, he said. Emergency responders in the area only had a respite from responding to drowning victims because the water along the border had recently receded.
Gonzales urged attention on the issue and said that most of the people seeking to come to the country were "fleeing economic persecution" with the aid of cartels and smugglers.
He also said the increase in migrants was unfairly taxing key ports of entry that let numerous people travel back and forth from Mexico and the U.S. for work or commerce or to see family.
Within the Del Rio, Texas, region, which includes Eagle Pass and which Gonzales represents, agents made 4,400 apprehensions on Tuesday -- the highest for any southwest border sector, according to the internal data.
"I suspect Christmas will be worse than today. And New Year's will be worse than today. We're going the absolute wrong direction," Gonzales told reporters, adding, "What about us?"
The situation is once again at the center of negotiations in Washington, where the Senate is inching closer to a possible deal early next year on boosting border security and further restricting which migrants can and can't come into the country.
The debate is already becoming a major issue in the 2024 presidential election, and President Joe Biden spoke Thursday with his Mexican counterpart, Andrés Manuel López Obrador, and both "agreed that additional enforcement actions are urgently needed, White House spokesman John Kirby told reporters.
No breakthrough will be made in Congress quickly: The Senate this week broke for the holiday without an agreement to tie border policy changes to Ukraine and Israel funding.
The White House is asking for money for 1,300 additional Border Patrol agents, 300 processing coordinators and support staff, 1,000 additional customs officers, 1,600 additional asylum officers and support staff to more quickly process the claims migrants make to avoid deportation. The supplemental funding would also allow for more deportation flights.
But Republicans say that must go along with major policy changes and, while many of the specifics are still being discussed behind closed doors, conservatives have called for significantly curbing who can seek lawful entry into the U.S.
Acting Customs and Border Protection Commissioner Troy Miller on Tuesday night described the situation at the border as a "serious challenge to the men and women of CBP."
"We continue to go after the smugglers and are implementing new measures to impose consequences on transportation companies including bus and van lines used by smuggling organizations and nefarious actors to move migrants through northern Mexico and to our southwest border," Miller said in a statement. "CBP and our federal partners need additional funding from Congress so that we can continue to effectuate consequences for those who do not use the established pathways."
As the number of migrant crossings increases, so do the number of removals and deportations -- which has drawn the ire of some activists and been cited by White House supporters as Republicans claim the administration is mismanaging the border.
The senior CBP official said that since last May, the number of migrants going through expedited removal has nearly tripled to as many as 900 per day, meaning more migrants are subjected to the consequences associated with a formal deportation.
More than half of the 5 million people arrested at the southern border during most of Biden's first term have been sent back, according to an analysis by the Cato Institute, a libertarian think tank.
Under former President Donald Trump's pandemic-era rules, many more migrants were expelled quickly, nominally out of public health concerns, but without bans on reentering the country.
Data suggests that just fueled a cycle of repeated crossings: Nearly half of the migrants processed under the pandemic restriction in budget year 2021 had previously been caught attempting to cross into the country, according to internal CBP figures.
People beyond the Western Hemisphere are on the move as well. For example, CBP data shows a significant increase in Chinese nationals attempting to enter the U.S. without authorization over the past year. Border Patrol agents in October apprehended more than 10 times as many Chinese citizens attempting to enter from Mexico compared to the previous year.
Last year also saw the highest number of Indian nationals apprehended by the Border Patrol since at least 2007, at about 43,000, according to agency data. And apprehensions of Russian nationals hit a high of about 7,400 based on data going back 10 years.
Those increases are unusual but still account for a relatively small fraction of the 2 million-plus apprehensions last year, the data shows.
There is another potential obstacle: The logistics of conducting deportations with some countries can prove difficult. U.S. authorities are required to verify an individual's nationality with their host country before conducting deportation.
"More typically, nonresponse or bureaucratic obstacles make returns difficult, if not impossible," global migration researcher Erlend Paasche wrote in a 2022 report. "If, for instance, the U.S. government approaches an origin country's embassy to request assistance in verifying identification and issuing travel documents as part of a removal, that country has various tools at its disposal to complicate the return."
With exceptions like Iran, it is relatively rare for countries to outright refuse to take back their own citizens, according to the Migration Policy Institute.
But China and Russia have been listed by the U.S. as two of the least cooperative countries when it comes to verifying and returning their would-be deportees. Other uncooperative countries include Cuba, Eritrea, Hong Kong, India, Iran, Iraq, Laos and Pakistan.
Countries can choose not to respond to U.S. requests or impose high bars for identity verification, making it difficult to prove the deportee's country of origin, according to Paasche.
"Deportation is a symbol of international power," Paasche wrote in the 2022 report. "Electorates in origin states may view readmission as a kind of betrayal, in which their government sides with a foreign country rather than its own nationals."
ABC News' Luke Barr, Cheyenne Haslett and Amanda Morris contributed to this report.