Homeland Security Secretary Alejandro Mayorkas gave a new warning to migrants seeking entry to the U.S., saying those who arrive at the border after Title 42 expires at midnight tonight will be ineligible to claim asylum.

Mayorkas addressed reporters Thursday in promised briefing on the Biden administration's plan to respond to a massive influx of illegal immigration that's come as the Title 42 public health order lifts. The government will now use its authority under Title 8 to impose steep penalties on migrants who cross the border illegally, including a minimum five-year ban on reentry and potential criminal prosecution, according to the secretary. 

"I want to be very clear: our borders are not open. People who cross our border unlawfully and without a legal basis to remain will be promptly processed and removed," Mayorkas said. 

The Biden administration's warning comes as Border Patrol agents made another 10,000 migrant apprehensions Wednesday, the third day in a row, according to Customs and Border Protection (CBP) sources. 

BIDEN ADMINISTRATION ADVERTISING ‘TOUGHER’ BORDER MEASURES AS THEY RELEASE THOUSANDS OF MIGRANTS

Mayorkas speaking

Homeland Security Secretary Alejandro Mayorkas speaks during the daily press briefing in the Brady Press Briefing Room of the White House in Washington, DC, on Thursday. "Our borders are not open," he said, hours before the U.S. implements a tough new immigration policy. (BRENDAN SMIALOWSKI/AFP via Getty Images)

Border Patrol has seen the highest daily totals ever recorded this week in anticipation of the end of Title 42. 

Currently, CBP has approximately 26,000 migrants in federal custody. Capacity across the southern border is about 19,000 and multiple sectors are well over capacity right now.

"We expected to see large numbers of encounters initially. We are already seeing high numbers of encounters in certain sectors," Mayorkas said. "This places an incredible strain on our personnel, our facilities and our communities with whom we partner closely. We prepared for this moment for almost two years and our plan will deliver results. It will take time for those results to be fully realized, and it is essential that we all take this into account." 

Sources tell Fox News that the priority right now for Border Patrol is avoiding images of overcrowding and processing migrants as fast as possible. Authorities earlier this week greenlighted "safe" mass street releases if CBP and non-governmental organization (NGO) partners cannot hold them. It means that the largest wave of mass releases in history has already begun and will continue in the coming days.

BORDER PATROL ENCOUNTERS 10,000 MIGRANTS FOR THIRD DAY IN A ROW AS NUMBERS SWELL BEFORE TITLE 42 DROPS

A U.S. Border Patrol agent talks with asylum-seekers

A U.S. Border Patrol agent talks with asylum-seekers waiting between the double fence along the U.S.-Mexico border near Tijuana, Mexico, in San Diego on Monday. (AP Photo/Denis Poroy)

Since 2020, both the Trump and Biden administrations have used Title 42 to expedite deportations because of the COVID-19 pandemic. In March, 46% of all encounters resulted in a Title 42 expulsion.

With the administration announcing Title 42 will be lifted, migrants have surged to the border in the belief that they are more likely to be released into the U.S. Though the Biden administration has made plans for the mass release of migrants, Mayorkas insisted that the border is not open and said human traffickers were spreading misinformation to those looking for a better life in America. 

"Smugglers have been long, hard at work, spreading false information that the border will be open," he said. "They are lying to people who are thinking of making their journey to our southern border. Know this: Smugglers care only about profits, not people. Do not risk your life and your life savings only to be removed from the United States."

AS MIGRANT WAVE HITS THE BORDER, MAYORKAS SAYS IT WILL ‘TAKE TIME’ FOR RESULTS OF TITLE 42 PLAN TO BE REALIZED

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Immigrants pray while hoping to be processed by U.S. border agents for asylum after crossing over from Mexico  in El Paso, Texas, on Tuesday. (John Moore)

He encouraged those seeking asylum in the U.S. to take advantage of the generous legal pathways the Biden administration has provided to immigrants, including the CBP One mobile app, which can schedule appointments at ports of entry. 

Pressed on whether the overcrowding at Border Patrol facilities and necessary release of some migrants undermines the administration's message, Mayorkas dodged the question.

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"Number one, we cannot overstate the extraordinary talent and heroism of the United States Border Patrol and the personnel of the Department of Homeland Security that are managing through an extraordinary challenge, and doing so successfully," he said. 

"Number two, it is very important to understand that the great majority of people will be removed if they do not qualify for relief under the laws of the United States." 

Fox News' Adam Shaw and Bill Melugin contributed to this report.