Marines prepare for Los Angeles deployment as protests spread across US

California will face off with Washington in court today (12 June) over President Donald Trump's deployment of US troops in Los Angeles after demonstrators again took to the streets in major cities to protest Trump's immigration crackdown.

Some 700 US Marines will be on the streets of Los Angeles by today or tomorrow, the military said, to support up to 4,000 National Guard troops in protecting federal property and federal agents, including on immigration raids.

Trump's decision to dispatch troops to Los Angeles over the objections of California Governor Gavin Newsom has sparked a national debate about the use of the military on US soil and further polarised the country.

Street protests have broken out in multiple cities besides Los Angeles, including New York, Chicago, Washington and San Antonio, Texas.

A federal judge in San Francisco will hear arguments Thursday as part of California's lawsuit against Trump. The state is requesting a temporary restraining order to block the troops' participation in law enforcement activities.

California ultimately wants a court ruling that returns its National Guard to the state's control and declares that Trump's action was illegal.

The LA protests broke out last Friday in response to a series of immigration raids. Trump in turn called in the National Guard on Saturday, then summoned the Marines on Monday.

"Los Angeles was safe and sound for the last two nights. Our great National Guard, with a little help from the Marines, put the LA Police in a position to effectively do their job," Trump posted on social media on Thursday. "They all worked well together, but without the Military, Los Angeles would be a crime scene like we haven't seen in years."

State and local leaders dispute that, saying Trump has only escalated tensions with an unnecessary deployment of federal troops, while Democrats nationally have condemned his action as authoritarian.

Trump is carrying out a campaign promise to deport immigrants, employing forceful tactics consistent with the norm-breaking political style that got him elected twice.

Los Angeles on Wednesday endured a sixth day of protests that have been largely peaceful but occasionally punctuated by violence, mostly contained to a few blocks.

In downtown LA, shortly before the second night of a curfew over a one square mile (2.5 square km) area on Wednesday night, police said demonstrators at one location threw commercial-grade fireworks and rocks at officers.

Another group of nearly 1,000 demonstrators was peacefully marching through downtown when police suddenly opened fire with less lethal munitions in front of City Hall.

Marlene Lopez, 39, a Los Angeles native, was demonstrating as flash bangs exploded just a few meters away.

"I am out here because of the fact that our human rights are being violated every day. If we give up, it's over. We have to stand our ground here in L.A. so that the nation will follow us," Lopez said.

An undetermined number of arrests were made, in addition to some 400 over the previous days.

New York police said an unknown number of people had been taken into custody on Wednesday after saying on Tuesday that 86 had been taken into custody, of which 34 were arrested and charged, while the others received a criminal court summons.

The protests are set to expand on Saturday, when several activist groups have planned more than 1,800 anti-Trump demonstrations across the country. That day, tanks and other armoured vehicles will rumble down the streets of Washington, DC, in a military parade marking the US Army's 250th anniversary and coinciding with Trump's 79th birthday.

Marines Trained for Crowd Control

US Marines will join National Guard troops on the streets of Los Angeles within 48 hours, officials said on Wednesday, and would be authorised to detain anyone who interferes with immigration officers on raids or protesters who confront federal agents.

A battalion of 700 Marines had concluded training specific to the LA mission, including de-escalation and crowd control, the US Northern Command said in a statement.

The Marines would join the National Guard under the authority of a federal law known as Title 10, not to conduct civilian policing but to protect federal officers and property, the military said.

"Title 10 forces may temporarily detain an individual in specific circumstances such as to stop an assault, to prevent harm to others, or to prevent interference with federal personnel performing their duties," the Northern Command said.

US Army Major General Scott Sherman, who commands the task force of Marines and Guardsmen, told reporters the Marines will not load their rifles with live ammunition, but they will carry live rounds.