WASHINGTON, United States (AFP) — The Republican-led US Congress delivered President Donald Trump an early victory in his promised crackdown on illegal immigration Wednesday as lawmakers green-lit a bill to expand pretrial incarceration for foreign criminal suspects.

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

"Criminal illegal aliens must be detained, deported and NEVER allowed back into our country," Mike Johnson, the speaker of the House of Representatives, said on X.

"The American people demand and deserve safety and security."

The law passed the upper chamber in a comfortable 64-35 vote earlier this week after sailing through the House of Representatives, with Republicans keen to highlight what they described as weak border security policies from Trump's predecessor Joe Biden.

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 meant it had to go back to the House for one last vote but it cleared that hurdle easily as 46 Democrats joined the Republicans, and it will now be the first piece of legislation Trump signs into law.

The 78-year-old has promised to crack down on illegal border crossings and carry out mass deportations. He has named Tom Homan, a veteran hardline immigration official, as his border chief.