An Illinois Army National Guard soldier and his cousin are expected to plead guilty to charges they conspired to provide material support to the Islamic State group.

The 22-year-old guardsman, Hasan Edmonds, and 29-year-old Jonas Edmonds are accused of plotting to attack the Joliet Armory with assault rifles and grenades. Prosecutors have alleged that Jonas Edmonds planned to wear his cousin's military uniform in the attack and that they hoped to kill as many as 150 people.

On Wednesday, prosecutors told a federal judge that the cousins likely will change their not guilty pleas. Their lawyers said details are still being worked out.

Both men are being held without bond and face up to 15 years in prison if convicted.