More than 1,000 people massed Wednesday in America's second biggest city, for a sixth day of protests, with the crowd peaceful as they marched through the streets.

A second night of curfew was in place as city leaders try to get a handle on the after-dark vandalism and looting that scarred a few city blocks in the 1,300 square kilometers metropolis.

"I would say for the most part everything is hunky dory right here at Ground Zero," protester Lynn Sturgis, 66, a retired school teacher, told AFP.

"Our city is not at all on fire, it's not burning down, as our terrible leader is trying to tell you."

The mostly peaceful protests ignited over a sudden escalation in efforts to apprehend migrants in the country illegally.

Pockets of violence -- including the burning of self-driving taxis and hurling stones at police -- were nothing the 8,500 officers of the Los Angeles Police Department had not dealt with before.

In Spokane, Washington, a night curfew was declared after police arrested more than 30 protesters and fired pepper balls to disperse crowds, police chief Kevin Hall told a news conference.

Trump won the election last year partly on promises to combat what he claims is an "invasion" by undocumented migrants.

He is now seizing the opportunity to make political capital, ordering the California National Guard to deploy despite Governor Gavin Newsom's objections, the first time a US president has taken such action in decades.

"We're going to have a safe country," he told reporters on his way into a performance of "Les Miserables" in Washington. 

"We're not going to have what would have happened in Los Angeles. Remember, if I wasn't there... Los Angeles would have been burning to the ground."

Around 1,000 of the 4,700 troops Trump deployed were actively guarding facilities and working alongside ICE agents, said Scott Sherman, Deputy Commanding General Army North, who is leading operations.

The rest -- including 700 active duty Marines -- were mustering or undergoing training to deal with civil disturbances, he said.

The Pentagon has said the deployment will cost taxpayers $134 million.

Governor Newsom, a Democrat widely viewed as eying a 2028 presidential run, has charged that Trump is seeking to escalate the confrontation for political gain.

He warned Tuesday that the unprecedented militarization would creep beyond his state's borders, claiming "democracy is under assault right before our eyes."

Lawyers for California were expected in court on Thursday to seek an order blocking troops from accompanying immigration officers as they arrest migrants.

Trump administration lawyers called the application a "crass political stunt."

Despite Trump's threats to deploy the National Guard to other Democratic-run states, protesters appeared undeterred.

Demonstrations were reported in St Louis, Raleigh, Manhattan, Indianapolis and Denver.

In San Antonio, hundreds marched and chanted near city hall, reports said, where Republican Texas Governor Greg Abbott has deployed the state's National Guard.

A nationwide "No Kings" movement was expected on Saturday, when Trump will attend a highly unusual military parade in the US capital.

The parade, featuring warplanes and tanks, has been organized to celebrate the 250th anniversary of the founding of the US Army but also happens to be the day of Trump's 79th birthday.

The Trump administration is painting the protests as a violent threat to the nation, requiring military force to support regular immigration agents and police.

But Los Angeles Mayor Karen Bass said the crisis had been manufactured in Washington.

"A week ago, everything was peaceful in the city of Los Angeles," she told reporters.

"Things began to be difficult on Friday when raids took place... that is the cause of the problems.

"This was provoked by the White House."

Arrests by masked and armed men continued Wednesday.

A pastor in the LA suburb of Downey said five armed men driving out-of-state cars grabbed a Spanish-speaking man in the church's parking lot.

When she challenged the men and asked for their badge numbers and names, they refused.

"They did point their rifle at me and said, 'You need to get back,'" Lopez told broadcaster KTLA.