CHICAGO — The suburban Chicago mother of a 19-year-old American facing a terrorist charge for trying to join the Islamic State militants accused the group on Tuesday of brainwashing youths into joining their ranks via social media. And she declared, “Leave our children alone!”

Mohammed Hamzah Khan’s mother cried softly as she read her statement in a federal courthouse lobby in Chicago. Minutes earlier, her son appeared in orange jail garb in an upstairs courtroom to plead not guilty to attempting to provide material support to a foreign terrorist group.

Zarine Khan, flanked by her husband, Shafi, said her family felt compelled to speak out in the wake of “unspeakable acts of horror” in Paris last week that killed 17. One gunman reportedly pledged allegiance to the Islamic State group, while two others cited al-Qaida.

“The venom spewed by these groups and the violence committed by them … are completely at odds with our Islamic faith,” she said.

Mohammed Khan, who lived with his parents in a middle-class Bolingbrook neighborhood, was arrested in October as he sought to sneak into Syria to join Islamic State militants.

Investigators later found a letter in Khan’s bedroom in which he apologized to his parents for leaving so abruptly. But he added he felt obliged to go from disgust with Western society and from anger over U.S.-backed bombing of Islamic State fighters, court filings alleged.

Adept Islamic State propagandists managed to woo Mohammed Khan into falsely believing they had established a legitimate Islamic government in parts of Syria and Iraq, Khan’s lawyer, Thomas Durkin, told reporters Tuesday.

“He’s a very devout, committed, thoughtful kid who bought into some very slick advertising,” Durkin said.