Republican presidential frontrunner Donald Trump suggested during a rally on Friday that refugees fleeing war-torn Syria are affiliated with Islamic State.

Syrian refuges "could be ISIS ... and by the way, it is turning out that they probably are ISIS," Trump told supporters in Rock Hill, South Carolina.

"There's so many men, they're so young, they are very strong. Where are the women? Where are the children?" he pondered, according to NBC News.

As Trump was making the comments, a woman wearing a hijab stood up in protest, and was promptly ejected from the audience.

Open gallery view Rose Hamid, in blue, is seen at the rally as Trump speaks. Credit: AP

A Muslim advocacy group on Saturday called on Trump to apologize after Hamid was removed by security personnel and booed by the crowd at the rally.

"The image of a Muslim woman being abused and ejected from a political rally sends a chilling message to American Muslims and to all those who value our nation's traditions of religious diversity and civic participation," said Nihad Awad, executive director of the Council on American-Islamic Relations (CAIR).

The woman, identified by CNN as Rose Hamid, a 56-year-old flight attendant, wore a t-shirt that read "Salam, I come in peace." She was also among several protesters, including immigration attorney Marty Rosenbluth, who happens to be Jewish, at the rally who wore yellow stars with the word "Muslim" written on them, reminiscent of the Stars of David Jews were forced to wear by the Nazis during WWII.

As she and Rosenbluth were both escorted out of the rally. When Hamid was being ejected, Trump supporters began booing and shooting at her. Hamid told CNN that one person yelled "You have a bomb, you have a bomb" in her direction. Trump recently made headlines over his controversial statement calling for a ban on Muslims entering the United States.

Open gallery view A protester wearing a yellow star stands as republican presidential candidate Donald Trump speaks during a campaign event in Rock Hill, South Carolina January 8, 2016. Credit: Reuters

Prior to the rally, Hamid told CNN that she only wanted to give Trump fans "an opportunity to meet" a Muslim.

"I figured that most Trump supporters probably never met a Muslim so I figured that I'd give them the opportunity to meet one," she said.

Ohio Governor John Kasich, a Republican presidential hopeful, said the crowd's response at Trump's rally in Rock Hill, South Carolina was inappropriate.

"We don't need to be shouting and booing and scaring somebody who decided to stand up and have some sort of silent protest," Kasich told reporters on the sidelines of a poverty summit in South Carolina on Saturday.

"What the heck is that about? We're not in high school. I mean, this is not some god-darn high school basketball game where we're booing the other team."