LOS ANGELES - The Mexican flag has become a flashpoint during protests in Los Angeles this week, waved by demonstrators proud of their heritage but cast by US President Donald Trump’s administration as heralding a “foreign invasion.”

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 Mr 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 on June 10 at Fort Bragg army base in North Carolina.

Republicans lined up behind Mr 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 polarising that it helped to get the legislation passed, argues Mr Mike Madrid, a Republican strategi...