Raids aimed at detaining and deporting migrants living in the US without legal permission are scheduled to commence on the first full day of President-elect Donald Trump's administration, according to sources cited by CBS, the BBC's US partner.

The operations, which have been threatened by Trump's "border tsar" Tom Homan, are expected to begin as soon as Tuesday in Chicago, a city with a significant migrant population. Trump has pledged to implement the largest deportation program in US history, with Homan emphasizing that criminals and gang members will be the primary targets of these raids.

In a recent interview with Fox News, Homan announced plans for a "big raid" across the nation and has previously referred to Chicago as "ground zero" for these mass deportations.

Trump, a Republican, had also promised large-scale deportations during his first presidential campaign in 2017. However, during his first term, he deported about half the number of immigrants as his predecessor, Democrat President Barack Obama, did during his first four years.

While the Immigration and Customs Enforcement (ICE) agency routinely deports illegal migrants, the upcoming operation, set to launch after Trump's inauguration on Monday, is expected to focus on "sanctuary" cities that limit cooperation with federal immigration authorities. Sources familiar with the plans informed CBS that ICE officials in the Chicago area recently asked agents to participate in the planned raids without notifying the agency's leadership in Washington, DC.

"January 21st, you're going to look for a lot of ICE agents in your city looking for criminals and gang members," Homan told a Republican gathering in Chicago last month. "Count on it. It will happen."

New York, Los Angeles, Denver and Miami are also due to be targeted with raids, the Wall Street Journal reports, citing unnamed sources familiar with the plans.

Some reports suggest that Trump could do away with a longstanding policy that has made churches off-limits for ICE arrests.

At a church in a mostly Latino neighbourhood of Chicago, worshippers shared their concerns with the BBC.

"I'm scared, but I can't imagine what people without papers are feeling," said D Camacho, a 21-year-old legal immigrant from Mexico who was in the congregation at Lincoln United Methodist Church in the Pilsen area last Sunday.

Reverend Emma Lozano said: "If someone with five children gets taken, who will take the children in? Will they go to social services? Will the family be divided?"

The rules under Democratic President Joe Biden were that ICE was generally to prioritise the arrest of illegal migrants who were serious criminals, had crossed the border recently or posed a national security threat.

While Trump's team has signalled that it will begin with migrants who had committed crimes, all illegal migrants - including those who have lived and worked in the US for many years and have no criminal history - may be more likely to be arrested and deported.

Immigration raids at construction sites where undocumented migrants are often employed are also expected to resume, after being discontinued by the Biden administration, according to CBS.

However, the operation could pose difficulties for officials - with limited custody space to hold detainees.

At the same time, the Laken Riley Act - named after a college student who was murdered last year in Georgia by a Venezuelan illegal migrant who was previously arrested for shoplifting - is expected to be passed by Congress next week.

The proposed legislation will require the federal government to detain migrants living in the US illegally who are suspected of criminal activity.

Source: BBC