Updated

Prosecutors say the younger siblings of a suburban Chicago man charged with seeking to join Islamic State militants were arrested with their brother.

Prosecutors revealed the arrests of Mohammed Hamzah Khan's siblings during a hearing Monday in Chicago federal court. They were arrested along with the 19-year-old Khan last month at O'Hare International Airport.

The siblings are ages 16 and 17. They haven't been charged in the case.

Attorneys didn't name the minors but said that they, like their brother, had expressed a passion for committing violence. They said the three not only had "barbaric rhetoric," but intended to act on it.

Khan is charged with seeking to provide material support to a foreign terrorist group. He was arrested trying to board a flight to Turkey.