A large majority of illegal crossings at the southern border are now happening in Arizona and California, shifting away from Texas counties. 

Sources with U.S. Customs and Border Protection told Fox News that over the last week of January, Border Patrol apprehended 32,809 illegal immigrants. 

Per CBP sources, 23,576 of them – 71.8% – were in Arizona and California. Notably, the numbers in Texas' Del Rio sector, which includes Eagle Pass, have fallen off a cliff. In December, the sector saw days of 3,000-4,000 illegal crossings per day. Over the last week, it has averaged around just 200. 

The shift could be attributed to two reasons. 

MAYORKAS, BLINKEN TO MEET WITH MEXICAN PRESIDENT TO TALK MIGRANT CRISIS AMID MASSIVE NUMBERS, NEW CARAVAN

Texas border

Migrants attempt to cross the border into the U.S. despite heightened security measures, in Ciudad Juarez, Mexico, on Feb. 1, 2024. (David Peinado/Anadolu via Getty Images)

Texas has locked things down on their side of the border, and Mexico has increased enforcement against migrants arriving in the Mexican state of Coahuila following Secretary of State Antony Blinken’s visit to Mexico in December. 

Mexico is now suddenly stopping migrants from boarding trains, and is removing migrants from their northern border down to their southern border following that meeting. 

And the migrants who do cross there now find a very unwelcoming posture from the state of Texas with legions of soldiers, troopers and razor wire, as well as the threat of arrest. It is unknown what the U.S. offered Mexico in return for this cooperation. 

Blinken in Mexico City

Secretary of State Antony Blinken arrives at the Palacio Nacional in Mexico City, on Dec. 27, 2023, in hopes of tackling surging migration. (Rodrigo Oropeza/AFP via Getty Images)

According to the State Department, Blinken joined Secretary of Homeland Security Alejandro Mayorkas and White House Homeland Security Advisor Liz Sherwood-Randall at a meeting in Mexico City with Mexican President Andrés Manuel López Obrador to "discuss unprecedented irregular migration in the Western Hemisphere and identify ways Mexico and the United States will address border security challenges, including actions to enable the reopening of key ports of entry across our shared border." 

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Mexican president meeting with Blinken

Mexican President Andrés Manuel López Obrador attends a meeting with Secretary of State Antony Blinken, Secretary Alejandro Mayorkas and U.S. Ambassador Ken Salazar in Mexico City on Dec. 27, 2023. (Rodrigo Oropeza/AFP via Getty Images)

Blinken, according to the State Department readout, was to "reaffirm the United States’ commitment to the Los Angeles Declaration for Migration and Protection, and underscore the urgent need for lawful pathways and additional enforcement actions by partners throughout the region."  

However, the Mexican government enforcement has not happened in other areas of the border, and Border Patrol’s San Diego sector and Tucson, Arizona, sector are now seeing the most activity. For instance, on Wednesday, CBP sources told Fox News there were 5,240 Border Patrol apprehensions of illegal immigrants at the southern border. The sources said 3,854 of them – 73.5% – were in Arizona and California for that day. 

The sources said none of the figures include CBP ports of entry/CBP One App or gotaways. The numbers represent only recorded Border Patrol apprehensions. 

California border

Workers set up a tent for processing asylum seekers along the U.S.-Mexico border fence on Jan. 30, 2024, in Jacumba Hot Springs, California.  (Qian Weizhong/VCG via Getty Images)

Border security has taken center stage in numerous states and in Congress, where Republicans are conditioning aid to Ukraine on a border security deal, and pushing to impeach Mayorkas. President Biden has said that he would shut down the border if given the emergency authority to do so as part of a deal, but Republicans say the president already has the power to do it.

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The Biden administration was handed a win by the Supreme Court last week in a decision allowing Border Patrol agents to cut concertina razor-wire that Texas had installed along the border near Eagle Pass while litigation continues. Part of the escalating standoff between the Biden administration and Texas over immigration enforcement, the Texas Military Department last month seized control of a city-owned Shelby Park in Eagle Pass, which had become one of the busiest spots for illegal crossings, and wouldn't let federal agents enter. 

Florida Gov. Ron DeSantis and South Dakota Gov. Kristi Noem offered to send personnel and other support to bolster Texas Gov. Greg Abbott's security efforts at the U.S.-Mexico border. 

The Associated Press contributed to this report.