For five days now protesters have held small and largely peaceful rallies against immigration raids in the sprawling city, as the rest of Los Angeles carried on largely as normal with red carpet premieres, awards shows, traffic and tourists.

But there have been some eyecatching -- albeit isolated and sporadic -- incidents of violence that produced dramatic images of protesters flying Mexican flags during clashes with law enforcement under smoke-filled skies.

It is those images that Trump and officials in his administration have seized on to help justify his extraordinary step of deploying thousands of US troops to the California city over the strident objection of local officials.

"The only flag that will wave triumphant over the streets of Los Angeles is the American flag -- so help me God," the president told cheering soldiers Tuesday at Fort Bragg army base in North Carolina.

Republicans lined up behind Trump to frame the protests as an invasion, with the Mexican flag as its symbol and the demonstrators as insurrectionists.

"Look at all the foreign flags. Los Angeles is occupied territory," top White House migration advisor Stephen Miller posted on X over footage of the demonstrations.

It is not illegal to fly foreign flags in the United States under the US Constitution's First Amendment, which guarantees freedom of speech.

But the Mexican flag has at times been a lightning rod in Los Angeles, the unofficial capital of the Mexican diaspora in the United States.

In 1994 the green, white and red banner was also waved by protesters as a sign of solidarity against legislation seeking to bar undocumented migrants from services including education and health care.

Then as now, it was seen by some as a symbol of anti-American defiance, becoming so polarizing that it helped to get the legislation passed, argues Mike Madrid, a Republican strategist who studies Latino voting trends.

"So it is a little bit odd to see the same strategy being used when it misfired so badly last time," Madrid, who authored the recent book "The Latino Century", told AFP.

- 'Great irony' -

Protesters who spoke to US media this week, including those who said they were American citizens, said they were waving the flag to show pride in their heritage and solidarity with those facing deportation.

Diana Mena, a 28-year-old US citizen with Mexican parents, said she had family in the US military

"As much as I understand that we had a privilege to come here, I feel like it's very important to know where we came from," she told AFP on Tuesday.

"I benefit from being in a place that has been able to provide me an opportunity to be able to advance, but that doesn't mean I'll ever forget my roots and my culture."

The strategist Madrid, who himself is of Mexican heritage, argues the ability for people to be proud of both cultures presents a paradox for Trump, after the Latino community's rightward shift helped propel him to victory in 2024.

That shift comes as more Latinos are born in the country rather than arriving as immigrants, transforming them into working-class voters rather than an ethnic minority, he said.

"The idea that we will respond... to an ethnic appeal over an economic or pocketbook appeal, is very very misguided, it's really a relic of the 1990s," he told AFP.

Many Latinos support Trump's crackdown on undocumented immigrants and illegal migration to the United States.

But the Latino vote is never cohesive "unless the community perceives itself to be under attack... It's very clear who the president is attacking here," Madrid said.

"The great irony is they're all moving towards him... That speaks to the dysfunction of the shrinking white Republican non-college-educated voter. Nativism animates the Republican Party's base."

A police officer at the US Capitol in Washington told CBS News it made no sense for Republicans to be outraged over Mexican flags at the LA protests.

He invoked the image of Trump supporters who stormed the Capitol on January 6, 2021 carrying the banner of the rebel Southern states who fought the United States during the Civil War from 1861 to 1865.

"They don't remember the Confederate flags on January 6?"