Actions to detain and deport migrants living in the US without permission should begin on the first full day of the new Trump administration, US media reports.
The operations — threatened by Donald Trump's “border czar” Tom Homan — could begin in Chicago, a city with a large immigrant population, as early as Tuesday, the New York Times and Wall Street Journal said.
Trump said he would preside over the largest deportation program in US history.
In an interview with Fox News this week, Homan promised a “major attack” across the country. He previously said Chicago will be ground zero for mass deportations.
Immigration and Customs Enforcement (ICE) deports illegal immigrants all the time. But the operation, which is expected to launch after Trump's inauguration on Monday, is expected to target so-called “sanctuary” cities that limit cooperation with federal immigration officials.
Along with Chicago, New York and Los Angeles are among dozens of US cities that have adopted “sanctuary” policies.
“On January 21st, you're going to be looking for a lot of ICE agents in your city looking for criminals and gang members,” Homan said at a Republican meeting in Chicago last month. “Count on it. It will happen.”
New York, Los Angeles, Denver and Miami are also to be attacked, the Wall Street Journal reported, citing unnamed sources familiar with the plans.
Under Democratic President Joe Biden, ICE has generally prioritized arresting illegal immigrants who are serious criminals, have recently crossed the border or pose a threat to national security.
Although Trump's team has signaled it will start with migrants who have committed crimes, all illegal migrants — including those who have lived and worked in the U.S. for many years and have no criminal history — are more likely to be arrested and deported.
Immigration crackdowns on construction sites where undocumented migrants are often employed are also expected to resume after being suspended by the Biden administration, according to CBS News, the BBC's US affiliate.
Ahead of an expected hardening of U.S. policy, more migrant farmworkers are seeking advice on dealing with immigration officials and finding temporary guardians for their children.
“The administration has not yet been sworn in, but people are already afraid,” Sarait Martinez, executive director of the Centro Binacional para el Desarrollo Indígena Oaxaqueño, which supports Mexican farm workers in California, told Reuters.
As well as the promise to deport millions of illegal migrants and the threats of workplace attacks, some reports suggest Trump may also scrap a longstanding policy that made churches off-limits to ICE arrests.
However, the upcoming actions are likely to create significant difficulties for officers – with limited space to hold detainees.
Meanwhile, Laken Riley's Law – named after a student who was killed last year in Georgia by a Venezuelan man previously arrested for shoplifting – is expected to be passed by US lawmakers next week.
The proposed law would require the federal government to detain migrants living in the U.S. illegally who are suspected of criminal activity — even if they have not been charged with any crime.