A curfew in downtown LA saw police make 25 arrests by morning, while US Marines are expected to make their first appearance on the streets

Protests against Donald Trump’s harsh immigration policies spread Wednesday across the United States despite a military-backed crackdown in Los Angeles and a threat by the Republican president to use “heavy force”.

In Los Angeles, where the unrest began last Friday, an overnight curfew in the downtown area saw police make 25 arrests by morning.

Heavily armed officers patrolled near government buildings, and storekeepers boarded up windows to protect against vandalism.

US Marines – ordered by Trump to deploy in addition to more than 4,000 National Guard soldiers – were expected to make their first appearance on the streets on Wednesday.