The Mexican flag has become a potent protest symbol

Elizabeth Torres, 36, held a Mexican flag outside the detention center in downtown Los Angeles on Sunday morning.

"I am a very proud American," said Torres, whose grandparents immigrated to the United States. "But I have to show support also for our Mexican brothers and sisters."

Throughout the weekend's protests, Mexican and other Latin American flags have emerged as protest emblems, which has angered the Trump administration's officials and supporters. Trump officials have cast flag wavers as insurrectionists and seemed to assume that they are not US citizens.

Stephen Miller, a top White House adviser, called out "foreign nationals, waving foreign flags, rioting and obstructing federal law enforcement attempting to expel illegal foreign invaders" in a social media post Sunday afternoon.

But for many protesters who are US citizens, the flag signifies pride in their roots, as well as solidarity with immigrants who are being targeted for deportation.

"They're the children and grandchildren of immigrants," said Chris Zepeda-Millán, a professor of Chicano studies at UCLA who has studied the immigrants rights movement in California. "They have no doubt in their own citizenship or their own belonging here, but they understand the racial undertones of the attacks on immigrants," he said.

"So you're getting this reaction of 'We're not going to let you make us be ashamed of where our parents and grandparents came from,'" Zepeda-Millán added.

On Saturday afternoon in Paramount, Eric Torres, 30 and no relation to Elizabeth Torres, waved a Mexican flag in front of sheriff's deputies in riot gear. Torres wore an oversize white T-shirt and baggy jeans, typical attire for many Chicanos in Los Angeles.

"I came out here to support my people and show them where we came from," he said. "My parents are immigrants. Most of the people right here have immigrant parents, so I'm here to support, show them our love."

The appearance of foreign flags at immigration protests is not new, nor is the outrage by those who deem it un-American. But American flags have been flown by protesters in Los Angeles, too, as they have in past protests against immigration crackdowns. And in Los Angeles this past week, fusions of the American flag with that of another country, such as Mexico or Guatemala, have regularly been seen waving among the demonstrators.

Some immigrant coalitions in the past have discouraged the waving of foreign flags, lest it feed anti-immigrant backlash. But Alfonso Gonzales Toribio, an ethnic studies professor at the University of California, Riverside, who has written about Latino immigrant rights movements, said that right now, immigrants "feel attacked."

He added, "I don't think we are going to be able to dissuade people" from flying the flag of their homeland. "It gives people a sense of pride."