Washington DC - The Senate voted Monday to expand pretrial incarceration for non-US nationals suspected of theft as the Republican-led Congress worked to deliver on Donald Trump's promises of a crackdown on immigration, hours after he began his second term.

The Laken Riley Act – which calls for the detention of undocumented immigrants charged with theft-related crimes – is named for a 22-year-old student murdered by a man with no papers who was wanted for shoplifting.

The American Civil Liberties Union warned that the legislation would have people jailed, "potentially for years" because "they were accused of nonviolent offenses."

The legislation passed the upper chamber in a 64-35 vote two weeks after sailing through the House of Representatives, with Republicans keen to highlight what they described as weak border security policies from Joe Biden, who left office on Monday.

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But the newly-inaugurated Senate – which flipped from Democratic to Republican control after November's election – added a tweak that expands mandatory detention to "crimes resulting in death or serious bodily injury."

That means it has to go back to the House for one last vote but it is expected to clear that hurdle and reach Trump's desk by the end of the week – the first bill he will sign into law.

"Now is the time to return to common sense. Now is the time to return to law and order," Alabama Republican Katie Britt said in a speech on the Senate floor ahead of the vote.

"We are a proud nation of immigrants. We are also a nation of laws, and the lawlessness ends today."

Trump has promised to crack down on border crossings and carry out mass deportations, and has named Tom Homan, a veteran hardline immigration official, as his border chief.

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The Republican president repeatedly spotlighted Laken Riley's case during his election campaign in racist tirades against undocumented migrants, blaming them for "poisoning the blood" of the country.

Twelve Democrats sided with Republicans in approving the bill. Others complained that it would cost $83 billion to implement the new law in the first three years – more than the Homeland Security Department's entire budget.

"That's a lot of money to spend on a bill that'll cause chaos, punish legal immigrants, & undermine due process – while drawing resources away from true threats," Patty Murray, of Washington state, said on X.