Hours before the pandemic-era Title 42 policy was set to end, Homeland Security Secretary Alejandro Mayorkas on Thursday warned migrants not to head for the United States’ southern border. 

“I want to be very clear: Our borders are not open,” Mayorkas said during a White House news briefing. 

Title 42 was lifted at 11:59 p.m. Eastern on Thursday. The policy, implemented by former President Donald Trump in response to COVID-19 fears, expelled migrants during the pandemic. 

The policy’s expiration is expected to bring a surge of migrants to the border — and Mayorkas said officials already are seeing high numbers of encounters there. The Biden administration, however, has been trying to send a message to migrants that they should not travel to the border but instead apply for legal pathways into the country using a mobile app. 

The federal government will return to Title 8 immigration law, used for decades leading up to the pandemic.

Migrants who try to enter the country unlawfully and don’t have a legal basis to the be in the U.S. will be swiftly expelled, Mayorkas said. They also face a five-year ban for reentry and criminal prosecution.

Meanwhile, the Biden administration is opening more legal pathways to enter the country, an approach Mayorkas said has dramatically reduced the number of illegal border crossings in recent months.

Mayorkas said the Biden administration has been preparing since 2021 for the end of Title 42. In anticipation of more encounters, the U.S. government has deployed to the border an additional 24,000 Border Patrol agents, 1,500 troops and more than 1,000 processing coordinators, as well as additional contractors and judges. 

“We are clear-eyed about the challenges we are likely to face in the days and weeks ahead, and we are ready to meet them,” Mayorkas said.

The Biden administration also has beefed up hiring of Border Patrol agents, is increasing the number of removal flights and has worked with Mexico to accept thousands of expelled migrants originally from Cuba, Haiti, Nicaragua and Venezuela

Mayorkas, however, said it will take time for the results of the administration’s approach “to be fully realized.”

At times Thursday, the Homeland Security chief attempted to speak directly to migrants, at one point cautioning them about smugglers falsely claiming the U.S. border is open.

“Smugglers care only about profits, not people,” he said. “Do not risk your life and your life savings only to be removed from the United States if and when you arrive here.”

The Biden administration’s solutions to reduce illegal border crossings include launching new and expanded family reunification parole programs for people from Colombia, Cuba, El Salvador, Haiti and Honduras and increasing the number of migrants legally admitted to the country through the CBP One app from 740 a day to as many as 1,000 a day. 

The Biden administration announced last month it is opening migrant processing centers in Central and South America to deter people from traveling to the border, although the program will take time to get up and running.

“To those who do not use our available lawful pathways, we will deliver tougher consequences using our immigration law, authorities,” Mayorkas said.

Mayorkas blamed the challenges at the border on inaction by Congress. 

“Our current situation is the outcome of Congress leaving a broken, outdated immigration system in place for over two decades despite unanimous agreement that we desperately need legislative reform,” he said. “It is also the result of Congress' decision not to provide us with the resources we need and that we requested.”

Republicans have long blamed President Joe Biden’s policies for increases in encounters at the border between law enforcement and migrants and called on the president to replace Title 42 with a similar policy. 

House Republicans were set to vote Thursday on a border security bill. 

Meanwhile, Sens. Thom Tillis, R-N.C., and Kyrsten Sinema, I-Ariz., told reporters Thursday they don’t think the Biden administration is ready for the expected surge of migrants.

“The end of Title 42 was premature, and the administration chose not to prepare adequately for it,” Sinema said. “The administration could extend the time of Title 42 on its own and actually do the preparation to prepare for an orderly end to Title 42.”

Florida Attorney General Ashley Moody sued to block the Biden administration from releasing large numbers of migrants into the U.S. when holding facilities reach capacity. A U.S. official told The Associated Press that Border Patrol agents were ordered Wednesday to begin releasing some migrants with instructions to appear at an immigration office within 60 days. 

Late Thursday, Judge T. Kent Wetherell blocked the quick-release policy for two weeks and scheduled a May 19 hearing on whether it should be extended.

Mayorkas told reporters Thursday the release strategy has been used in the past and that individuals who do not report to an immigration office would be subject to arrest. He added that “the vast majority” of those who are not eligible for legal entry will be removed from the country “in a matter of days if not weeks.”

In a statement, Customs and Border Protection said it would comply with Wetherell's order but called it “harmful ruling that will result in unsafe overcrowding ... and undercut our ability to efficiently process and remove migrants.”