A Pennsylvania man is expected in court a day after a grand jury indicted him for allegedly trying to assist the Islamic State extremist group, advocating violence against American citizens and helping people travel to Syria.

A detention hearing and arraignment was scheduled for Wednesday in federal court for 19-year-old Jalil Ibn Ameer Aziz. He’s being held on charges of conspiracy and trying to help a group designated by the U.S. government as a foreign terrorist organization.

Prosecutors say the Harrisburg man used Twitter to spread Islamic State propaganda and had a bag with ammunition, suggesting he may have been planning an attack.

Charging documents describe him as a fervent Islamic State supporter and someone who “espouses violent jihadist beliefs.”

A message seeking comment from his lawyers wasn’t immediately returned.

(AP)