WASHINGTON – Sen. Bernie Sanders' campaign responded to protesters who displayed a flag bearing a swastika during his rally Thursday night in Phoenix.

Images of the flag in the crowd circulated on social media posts, which showed the flag unfurling as the crowd cheered for the Vermont senator after he declared how loud they were. The cheers quickly turned to boos as they saw the flag.

Sanders' supporters appeared to rip the flag from the protester's hands, and police escorted him out.

Addressing reporters Friday morning, Sanders said that he not only speaks as a Jewish American, but he "speaks for the families" of the more than 400,000 American troops who died fighting in World War II "against fascism."

"It is horrific, beyond disgusting to see that in the United States of America there are people who would show the emblem of Hitler and Nazism," he continued.

If elected, Sanders would be the first Jewish president. Many of his relatives were killed in the Holocaust.

From Arizona: Bernie Sanders rally in Phoenix, Nazi flag video surfaces

At the time, Sanders did not appear to notice the man, though he later said, “Whoever it was, I think they’re a little outnumbered tonight. And more importantly they’re going to be outnumbered in November.”

Later, Sanders' communications director Mike Casa told Ruby Cramer of BuzzFeed News that Sanders “is aware of the flag with the swastika on it and is disturbed by it.”

Sara Pearl, supervising producer for Sanders' campaign, tweeted Friday morning that "Last night at Bernie’s rally in Arizona, someone horrifically unfurled a Nazi flag with a swastika on it. Earlier we had just released this video of what it means for Jews like me to elect our first Jewish President who will stand up to white nationalism and hate."

Steven Slugocki, chairman of the Maricopa County Democratic Party, of which the county seat is Phoenix, tweeted that, "We can argue about which candidate should get the Dem nomination, but antisemitic acts have no place in this world. This is absolutely abhorrent."

Rep. Ilhan Omar, D-Min., condemned the protester via Twitter. Omar endorsed Sanders and has been campaigning for him. She wrote, "This is an appalling display of anti-Semitism against a man whose family perished in the Holocaust."

The incidence again raised the issue of security for presidential candidates.

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Acting Homeland Security Secretary Chad Wolf was urged Wednesday to consider Secret Service protection for Sanders and former Vice President Joe Biden, the two top contenders for the Democratic nomination. Both campaigns have been operating without government protection, but the Secret Service's involvement appears more likely as the presidential campaign heats up.

The request from House Homeland Security Committee Chairman Bennie Thompson, D-Miss., came a day after protesters rushed a stage in Los Angeles where Biden was celebrating a string of Super Tuesday primary wins. Biden was not harmed by the sign-waving protesters, who were repelled by his wife, Jill Biden, and a campaign aide.

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In a statement yesterday addressing the calls for support, the Secret Service said, "At this time, no candidates have requested protection."

Sanders' Thursday night event was also interrupted by multiple supporters of President Donald Trump.

Former vice president Joe Biden, who is Sanders' main competitor for the nomination, tweeted out his condemnation of the protester, saying, "I don't care who you're supporting, attacks like this against a man who could be the first Jewish President are disgusting and beyond the pale. Hatred and bigotry have no place in America — and it's up to all of us to root out these evils wherever they're found."

Amy Spitalnick, executive director of Integrity First For America, called the display "sickening."

The group, which is funding a lawsuit against the organizers of the Charlottesville march in federal court, put out a statement, saying they are "horrified."

"These are not isolated incidents – they are part of a wave of anti-Semitism, neo-Nazism, and white supremacy and we cannot let this become normalized."

Contributing: Kevin Johnson