According to US media reports, raids to detain and deport immigrants living in the United States without permission will begin on the first day of the new Trump administration.

The New York Times and Wall Street Journal said the operations could begin as early as Tuesday in Chicago, a city with a large immigrant population, amid threats from Donald Trump’s “border czar” Tom Homan.

Trump says he will oversee the largest deportation program in U.S. history.

In an interview with Fox News this week, Homan promised a “big search” across the country. he had previously said Chicago to become ‘ground zero’ for mass evictions.

The Immigration and Customs Enforcement (ICE) agency has been deporting illegal immigrants. However, actions expected to begin after Trump takes office on Monday are expected to target so-called “sanctuary” cities that restrict cooperation with federal immigration officials.

Along with Chicago, New York City and Los Angeles are among dozens of U.S. cities that have adopted “sanctuary” policies.

“On January 21, you’re going to have a lot of ICE agents in your city looking for criminals and gang members,” Homan told a Republican rally in Chicago last month. “Believe it. It’s going to happen.”

New York, Los Angeles, Denver and Miami will also be targeted for raids, the Wall Street Journal reported, citing unnamed sources familiar with the plan.

Under Democratic President Joe Biden, ICE has typically prioritized apprehending illegal immigrants who are serious criminals, have recently crossed the border or pose a threat to national security.

Although the Trump team has said it would start with immigrants who commit crimes, all illegal immigrants — including those who have lived and worked in the United States for years and have no criminal records — are more likely to be arrested and deported.

Immigration raids on construction sites that often employ undocumented immigrants are also expected to resume after being halted by the Biden administration, BBC America partner CBS News reported.

Ahead of an expected tightening of U.S. policy, more migrant workers have been seeking advice on dealing with immigration officials and appointing temporary guardians for their children.

“The government hasn’t been sworn in yet, but people are already scared,” Salette Martinez, executive director of the Oaxacono Indian Development Center, which supports Mexican farmworkers in California, told Reuters.

In addition to pledging to deport millions of illegal immigrants and threatening workplace raids, some Reports suggest Trump may also repeal a long-standing policy that bans ICE from arresting churches.

However, the upcoming raids could pose significant difficulties for officials – with limited detention space to hold detainees.

Meanwhile, the Laken Riley Act — named after a college student who was murdered in Georgia last year by a Venezuelan man who had been arrested for shoplifting — is expected to be enacted next year. Zhou was approved by U.S. lawmakers.

The proposed legislation would require the federal government to detain immigrants living in the U.S. illegally who are suspected of criminal activity — even if they are not accused of any crime.