The Jewish Telegraphic Agency, a wire service for global Jewish news, reported that "at least three Jews were taken to the hospital as a result of the clashes." This chaos went on for about 40 minutes, Le Bail-Kremer said, before police arrived in droves.

"The scene was very violent, with terrifying and anti-Semitic slogans," said Le Bail-Kremer, who happens to be involved with SOS Racisme, a French anti-racism organization. "I was very, very anxious and shocked. It looked like a war."

Trying to 'turn the other cheek'

As she stepped forward to make closing remarks at a pro-Gaza demonstration she organized over the weekend in Atlanta, Abdullatif said she saw the crowd turn the other way.

Across the street, she said, there were two men with Israeli flags who discharged pepper spray toward the crowd.

"I kept telling everybody, just keep your backs facing them, don't give them any attention," said Abdullatif, a Palestinian-American who helped found the Atlanta-based Movement to End Israeli Apartheid-Georgia.

But on the fringes of the crowd, she said, pro-Palestinian demonstrators started shouting back.

"I said, 'Stop talking to them. This is only fueling a lot of this. Ignore them. Turn the other cheek,' " she said. "But easier said than done."

Eventually, things simmered down, but hours after the protest, Abdullatif said her phone rang with a surprising message.

A man on the other end, she said, threatened to report her to the Georgia Bureau of Investigation, accusing her of aiding terrorism. He said he was happy about recent bombings in Gaza, "that everybody deserves to be killed, and that I should be careful, my name is out there," Abdullatif said.

Abdullatif told him that she did nothing wrong. But she said the conversation, which was followed by days of text messages and Facebook posts in the same vein, rattled her.

"I've never seen an opposing side go to that extreme," she said.

What if they found where she lived or targeted her family?

"My biggest concern is if we have another demonstration, I don't want anything like this to happen," Abdullatif said. "This is the exact stuff we're protesting against. I don't want to be connected to people fighting people over anything."

But that doesn't mean she'll stop speaking out. She sent photos of the weekend protest to her uncle in Gaza City, whose neighborhood was recently destroyed in a bombing. She hopes the photos will let him know that the world is watching.

"It's just such a sad situation. It's 2014. We should have figured out by now that barbaric acts of violence don't accomplish anything from any side of it," she said. "We live in a modern society. We know that this is never a way to create a solution."

'I saw my flag on the ground'

On Sunday, a peaceful pro-Israel rally in Los Angeles turned ugly after demonstrators came face-to-face with counterprotesters in a pickup who were waving Palestinian flags.

What exactly happened, however, depends on who you ask.

Four people were arrested on suspicion of assault with a deadly weapon, accused of driving up to the protest in a truck and hitting pro-Israel demonstrators with handheld flagpoles, CNN affiliate KTLA reported, citing police.