A group of 15 white men who support the display of the Confederate battle flag have been indicted as a street gang for allegedly threatening unarmed black people who were attending a child's birthday party in Georgia last summer.

On Monday, a Douglas County grand jury indicted the men, who are members of the "Respect the Flag" group, on terrorist charges and for violating the state's street gang law, reports The New York Times. Two men also are facing additional charges for allegedly hitting and kicking a man at a gas station on the same day.

The incident occurred on July 25 when witnesses say the men ambushed a black child's birthday party, shouting death threats and racial slurs.

Video footage captured the men riding past the group of African Americans in a convoy of pickup trucks while brandishing the Confederate Battle flag, along with the American flag. In one video, someone can be heard shouting the N-word while witnesses accused them of displaying guns, tire irons and knives.

"That is a threat! That is a threat, officer!" one emotional woman repeatedly shouts in a video.

"We respect the rights of all citizens to exercise their first amendment right, but we're going to require them, while doing that, to respect the rights of all of the citizens, to feel safe," said Douglas County district attorney Brian Fortner at a press conference Monday, reports The New York Daily News.

Only four out of the 15 indicted men had been arrested as of Monday evening. Their bail has been set at $9,000 each, reports 11Alive.

According to Morris Dees, the Southern Poverty Law Center's co-founder and chief trial attorney, the group's actions were "reminiscent of the Ku Klux Klan."

"These cowards chose unarmed African Americans enjoying a peaceful birthday party to vent their violent racist hatred," he said in a statement Monday. "I applaud the foresight and courage of District Attorney Brian Fortner for nipping this dangerous activity in the bud before innocent citizens are hurt," he added.